ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Articles  (129)
  • Other Sources
  • 73.20.Dx  (74)
  • Excitons and related phenomena (including electron-hole drops)  (55)
  • Springer  (129)
  • American Chemical Society
  • American Geophysical Union
  • American Institute of Physics
  • American Institute of Physics (AIP)
  • American Physical Society
  • Blackwell Publishing Ltd
  • Institute of Physics
  • 2000-2004  (14)
  • 1995-1999  (115)
  • 1970-1974
  • 1955-1959
  • 1945-1949
  • 1935-1939
  • Physics  (129)
  • Natural Sciences in General
Collection
  • Articles  (129)
  • Other Sources
Keywords
Publisher
  • Springer  (129)
  • American Chemical Society
  • American Geophysical Union
  • American Institute of Physics
  • American Institute of Physics (AIP)
  • +
Years
Year
  • 1
    ISSN: 1432-0649
    Keywords: 78.47.+p ; 73.20.Dx ; 71.35,+z
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We use femtosecond time-resolved transmission spectroscopy to study the density and time dependence of transient absorption changes of CdSe nanocrystals. Our data show pronounced absorption saturation up to complete bleaching of the lowest optical transition. At high carrier density the nonlinear spectra show several peaks that can be related to the two lowest quantized electron states. Thetime dependence of the carrier-induced absorption changes indicates an ultrafast relaxation process within the strongly broadened absorption lines.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 17 (1995), S. 1315-1322 
    ISSN: 0392-6737
    Keywords: Excitons and related phenomena (including electron-hole drops) ; Time resolved optical spectroscopies and other ultrafast optical measurements in condensed matter ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary The concept of coherence due to optical excitation of an ensemble of two-level atoms is relatively simple and well established. For the laser-excited electron-hole pairs or excitions in a semiconductor, the Pauli exclusion and the Coulomb interaction lead to the necessary evolution of the theory of coherence to incorporate the spin degree of freedom, the filling of phase space, the excitons and particularly, their correlation. We have developed two theoretical approaches: one using the Feynman diagrams and one in terms of a force-force correlation function. The former gives us a pictorial way to describe the optical processes and the latter gives us a prescription for computation beyond the perturbative approach. In this paper, we will attempt to use simple physical pictures based on our theory to describe the time development of the coherence, the role of correlation, the dependence on the polarization of light, and the nonlinear time-resolved optical experiments which measure the coherence.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 17 (1995), S. 1429-1433 
    ISSN: 0392-6737
    Keywords: Excitons and related phenomena (including electron-hole drops) ; Localised single-particle electronic states (excluding impurities) ; Photoluminescence ; II–VI semiconductors ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary Time-resolved photoluminescence experiments in a wide carrier density range up to and beyond the threshold for stimulated emission in ZnSe/ZnS x Se1−x superlattices are presented. Different localisation mechanisms of free excitons are identified giving rise to different radiative recombination channels. At high carrier density localised energy states merge into miniband that allows for exciton-exciton interaction, such as screening of the free-exciton absorption and inelastic exciton-exciton scattering.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 17 (1995), S. 1407-1412 
    ISSN: 0392-6737
    Keywords: Excitons and related phenomena (including electron-hole drops) ; Surface and interface electron states ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary We have investigated the fine structure of luminecence of CdSe nanocrystals observed with size-selective excitation. We show that the luminescence line closest to the laser arises from the recombination of the optically forbidden A-exciton. Radiative recombination occurs via a phonon-assisted virtual transition to theB-exciton state. The electron-hole exchange energy obtained from the experimental results strongly increases with decreasing nanocrystal size as expected from the increasing overlap of the electron and hole wave functions. The size dependence is in good agreement with the theoretical predictions.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 17 (1995), S. 1423-1427 
    ISSN: 0392-6737
    Keywords: Excitons and related phenomena (including electron-hole drops) ; Surface and interface electron states ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary Normalized reflection spectra in GaInAs/GaAs quantum wells are shown for two sets of samples with different alloy concentration (x=9% and 18.5%) and well thickness ranging from 1.5 nm to 25 nm. All samples were grown on (001) GaAs surface by Molecular Beam Epitaxy and characterized by RHEED and X-ray reflection diffraction. Exciton envelope function in effective mass approximation and optical response in polaritonic schema are computed. Normalized reflection spectroscopy has shown itself to be a well suited technique in order to study structural and electronic properties of confined quantum structures.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 17 (1995), S. 1447-1452 
    ISSN: 0392-6737
    Keywords: Excitons and related phenomena (including electron-hole drops) ; Optical properties of thin films, surfaces, and layer structures (superlattices, heterojunctions, and multilayers) ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary We investigate the absorption spectrum and the distribution of radiative decay times for two-dimensional excitons in semiconductor quantum wells, as affected by an adiabatic white-noise random potential. Such a potential could result from atomic-scale fluctuations in the composition of an alloy semiconductor, or in quantum well thickness. We find in general that the shortest radiative decay time is directly proportional to the inhomogeneous width of the exciton line in absorption, itself proportional to the correlation parameter for the random potential.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 17 (1995), S. 1473-1479 
    ISSN: 0392-6737
    Keywords: Surface and interface electron states ; Excitons and related phenomena (including electron-hole drops) ; Polaritons (including photon-phonon and photon-magnon interactions) ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary We report the evidence of exciton-polariton centre-of-mass quantization in II–VI quantum wells consisting of ternary alloy. Absorption and photoluminescence studies on Zn0.89Cd0.11Se/ZnSe quantum wells, covering the intermediate region between two- and three-dimensional exciton behaviour, exhibit distinct optical resonances in the high-energy tail of the free-exciton structure. We reproduce the well width dependence of the centre-of-mass states by modeling the optical response of the QWs with a thin-slab variational wave function, which takes into account non-adiabatic terms.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    ISSN: 0392-6737
    Keywords: Studies of specific magnetic materials ; Optical properties of thin films surfaces and layer structures (superlattices, heterojunctions and multilayers) ; Excitons and related phenomena (including electron-hole drops) ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary Two qualitatively different e-h systems have been investigated in undoped CdTe/Cd0.88Mn0.12Te and Cd0.97Mn0.03 Te/Cd0.75Mn0.25 Te QWs at 2 K and magnetic fields up to 14 T, namely a strongly spin-depolarized system in the CdTe QW and a highly spin-polarized one in the Cd0.97Mn0.03 Te QW. The interaction of the spin-aligned excitons is repulsive. In contrast, in the spectra of a dense spin-depolarized excitonic system an additional well pronounced emission lineM was observed at approximately 5 meV below the excitonic line. This line is assigned to the emission of molecules consisting of excitons with opposite spins of both electrons and holes.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 17 (1995), S. 1573-1578 
    ISSN: 0392-6737
    Keywords: Time-resolved optical spectroscopies and other ultrafast optical measurements in condensed matter ; Excitons and related phenomena (including electron-hole drops) ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary We report on the observation of an electric-field-induced electric-dipole moment of biexcitonic molecules in a GaAs/Al0.3Ga0.7As superlattice. The macroscopic oscillating electric field, associated with the microscopic wave packet dipole moments, is monitored by time-resolved transmittive electro-optic sampling. The field dependence of the biexcitonic binding energy is detected by transient four-wave mixing. From these experiments, an ultrafast non-resonant excitation mechanism of biexcitons is inferred.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 17 (1995), S. 1255-1264 
    ISSN: 0392-6737
    Keywords: Excitons and related phenomena (including electron-hole drops) ; Polaritons (including photon-photon and photon-magnon interactions) ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary We develop the bipolariton concept for a quasi-2D excitonic molecule (m) in quantum wells (QWLs). The bipolariton wave equation, which includes both the exciton-exciton (x-x) attraction and thex-photon (γ) coupling, is analysed. In the 2D bipolariton model, a quasi-2Dm exists in QWLs mainly as two quasi-boundsurface polaritons and, consequently, decays mainly into two outgoing surface polaritons. In quasi-2D GaAs QWLs the polariton renormalizations give rise to a «Mexican hat» structure in them dispersion at small momenta together with a considerable increase of both them effective binding energy ɛ m and the inversem radiative lifetimeГ m . A van Hove singularity in the joint density of polariton states is responsible for this effect.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 11
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 17 (1995), S. 1657-1662 
    ISSN: 0392-6737
    Keywords: Excitons and related phenomena (including electron-hole drops) ; Polaritons (including photon-phonon and photon-magnon interactions) ; Dynamics of nonlinear optical systems ; optical instabilities, optical chaos, and optical spatio-temporal dynamics ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary The linewidth of the microcavity exciton polariton is studied by onresonant and off-resonant photoluminescences. The two main contributions to the linewidth are caused by radiative loss and phonon scattering. The oscillator strength is found to be unmodified by the exciton-phonon coupling. Comparison is made between theory and experiment.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 12
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 17 (1995), S. 1717-1722 
    ISSN: 0392-6737
    Keywords: Excitons and related phenomena (including electron-hole drops) ; Time-resolved optical spectroscopies and other ultrafast optical measurements in condensed matter ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary The coupled dynamics of free carriers and excitons after non-resonant excitation with short laser pulses is investigated by means of an Ensemble Monte Carlo method which includes phonon-assisted formation and dissociation of free excitons. Simulations for bulk GaAs reveal that excitonic binding under participation of LO phonons is a very fast and effective process. The temporal rise of exciton luminescence depends on the particular excitation conditions and is determined by all interaction mechanisms in the system.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 13
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 17 (1995), S. 1747-1751 
    ISSN: 0392-6737
    Keywords: Polaritons (including photon-phonon and photon-magnon interactions) ; Excitons and related phenomena (including electron-hole drops) ; Quantum optics ; Electron states in low-dimensional structures (including quantum wells, superlattices, layer structures, and intercalation compounds) ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary A great interest in the study of exciton-photon coupling in resonant optical media such as semiconductor microcavities is currently developing both in experiments and in theory. We investigate the spectral response of a new semiconductor quantum system in which the cavity material itself is the active medium. If the Fabry-Perot quasi-mode is carefully tuned on the excitonic transition of the cavity bulk material, strong exciton-photon coupling takes place and produces new features such as a Rabi-like splitting as large as that observed in quantum well microcavities and comparable optical absorption. In addition, the polaritonic spatial dispersion and the quantization of the centre-of-mass motion introduce remarkable fine structures which are absent in the quantum well case. We demonstrate the above effects from a spectroscopic analysis of GaAs cavities, using standard reflectance and photoluminescence techniques. The experimental results are further clarified with theoretical calculations performed with an adapted transfer-matrix approach. The case of semi-cavities is finally considered and a new way to control the exciton-photon interaction in our system is achieved tailoring the photonic wave function with a change in the reflectivity phase of the mirrors.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 14
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 17 (1995), S. 1801-1805 
    ISSN: 0392-6737
    Keywords: Excitons and related phenomena (including electron-hole drops) ; Time-resolved optical spectroscopies and other ultrafast optical measurements in condensed matter ; Electron states in low-dimensional structures (including quantum wells ; superlattices ; layer structures ; and intercalation compounds ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary Disorder-induced Rayleigh scattering of excitons in quantum wells is investigated theoretically. For classical excitions (long-range spatial correlation), the disorder average can be performed exactly. For the full problem, a kinetic equation with «weak memory» for the excition distribution is derived which coincides with the classical result in the appropriate limit. The theoretical results are compared with recent experimental data on femtosecond time-resolved luminescence explaining well the finite rise time and the heavy-light-hole beating.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 15
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 17 (1995), S. 1323-1332 
    ISSN: 0392-6737
    Keywords: Excitons and related phenomena (including electron-hole drops) ; Polaritons (including photon-phonon and photon-magnon interactions) ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary We present an extensive set of absorption and PL measurements on semiconductor microcavities in the strong-coupling regime. We observe strong coupling from 110 K to room temperature. We look at the behaviour of the photoluminescence for different exciton-photon detuning. We discuss this data using two different pictures, the first is a non-interacting (uncoupled) picture of an exciton in a cavity filter. The second model is that of a cavity polariton and this explains the observed dynamics in the strong-coupling regime. We show how the opposing needs of strong coupling and high photoluminescence extraction efficiency can be reconciled.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 16
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 17 (1995), S. 1343-1347 
    ISSN: 0392-6737
    Keywords: Excitons and related phenomena (including electron-hole drops) ; Polarons and electron-phonon interactions ; Electron states in low-dimensional structures (including quantum wells, superlattices, layer structures, and intercalation compounds) ; III-V compounds and systems ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary We have calculated the binding energies of excitons in quantum well structures based on ionic semiconductors by including the electron-hole interactions with the longitudinal-optical-phonon field. We have taken into account these interactions by using different effective interaction potentials between the electron and the hole as derived by Haken, Aldrich and Bajaj, and Pollman and Buttner. We have calculated the binding energies of excitons in several ionic quantum well structures as functions of well width using these effective potentials following a variational approach. We find that the values of the exciton binding energies calculated using these potentials are always larger than those, obtained using a Coloumb potential screened by static dielectric constant.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 17
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 17 (1995), S. 1509-1512 
    ISSN: 0392-6737
    Keywords: Excitons and related phenomena (including electron-hole drops) ; III-V Compounds and systems ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary The reflectance spectra of GaN/6H-SiC, films and the absorption spectra of GaN/Al2O3 films were studied and several fundumental parameters of GaN-energy positions of exciton, resonances ω0, damping constants⩾s, longitudinal-transverse splittings ωLT and the oscillator, strengthsf of the exciton states were determined. A blue shift and broadening of the luminescence band were observed in the luminescence spectra of GaN quantum dots. The mean dot radius in the sample was estimated to be about 4.5nm.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 18
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 17 (1995), S. 1531-1536 
    ISSN: 0392-6737
    Keywords: Excitons and related phenomena (including electron-hole drops) ; Time-resolved optical spectroscopies and other ultrafast optical measurements in condensed matter ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary The localization dynamics of excitons within growth islands of GaAs/Al x Ga1−x As single quantum wells (SQW) have been investigated by time-resolved photoluminescence spectroscopy (TRPL). Several samples with different substrate misorientation and growth interruption times are compared with regard to the photoluminescence (PL) emission dynamics. For monolayer (ML) islands larger than the exciton radius,i.e. long growth interruption, the time evolution of the different PL peaks reflects the transfer of free excitons between growth islands as well as the localization within a single growth island. The samples with shorter growth interruption reveal a much less pronounced PL splitting due to ML islands. The dynamics appears to be mainly determined by exciton localization to thicker ML islands. The density of localization centres is larger for the sample grown on misoriented substrates.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 19
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 17 (1995), S. 1555-1559 
    ISSN: 0392-6737
    Keywords: Nonlinear optics ; Optical properties of thin films, surfaces, and thin layer structures (including superlattices, heterostructures, and intercalation compounds) ; Electron states in low-dimensional structures (including quantum wells, superlattices, layer structures, and intercalation compounds) ; Excitons and related phenomena (including electron-hole drops) ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary In a system comprising an organic layer coupled to a semiconductor layer, if the energy of the Frenkel exciton in the first is close to that of the Wannier exciton in the second, the lowest electronic excitations can be described as hybrid resonances. These new excitons give rise to very pronounced optical non-linearities because they have at the same time large oscillator strengths, typical of Frenkel excitons, and large radii, typical of Wannier excitons. The results of a microscopic calculation of the optical properties of such a system are presented and discussed: compared with the usual semiconductor quantum wells, enhancements of two orders of magnitude both in the size of the susceptibility (linear part) and in its relative change with increasing excitation density (Kerr non-linearity) are predicted.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 20
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 17 (1995), S. 1383-1387 
    ISSN: 0392-6737
    Keywords: III–V semiconductors ; Electron states in low-dimensional structures (including quantum wells, superlattices, layer structures, and intercalation compounds) ; Excitons and related phenomena (including electron-hole drops) ; III–V compounds and systems ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary We report an experimental study on a large set of InGaAs/GaAs quantum well structures by means of continuous-wave photoluminescence and photoluminescence excitation. The luminescence spectrum at low temperature systematically exhibits a doublet structure whose lineshape is very sensitive to the excitation energy. Accordingly, the excitation spectra detected by monitoring the emission at the two different luminescence peaks have very different profiles, with peaks and/or dips which are not directly related to absorption resonances. As a matter of fact, the anomalies disappear when increasing the temperature or when using an optical bias with energy above the GaAs energy gap. In these cases, the excitation profiles recover the behaviour typical of 2D systems.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 21
    ISSN: 0392-6737
    Keywords: Excitons and related phenomena (including electron-hole drops) ; Optical properties of thin films surfaces and layer structures (superlattices, heterojunctions and multilayers) ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary We report here on the study of the optical properties of ZnCdSe−ZnSe quantum structures elaborated by metalorganic chemical vapour deposition (MOCVD). The band structure is experimentally investigated by means of photoluminescence and photoreflectance. We have computed the exciton binding energies for heavy- and light-hole excitons in the context of a self-consistent two-parameter trial function. As a complement, we study the temperature dependence of the photoluminescence intensity under both direct and indirect photoexcitation in graded-index separate confinement heterostructures based on these materials.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 22
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 17 (1995), S. 1787-1790 
    ISSN: 0392-6737
    Keywords: Excitons and related phenomena (including electron-hole drops) ; II–VI compounds and other chalcogenides ; II–VI semiconductors ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary We report on the observation of the doubly resonant secondary emission involving 2s and 1s exciton states. The resonance conditions have been realized in CdTe/Cd1-xMnx Te quantum well structures by magnetic-field tuning of the 2s-1s energy spacing to the LO-phonon energy. Theoretical analysis shows the doubly resonant process to be indirect, with hot 1s excitons acting as intermediate states. It is concluded that the resonance width of 2.6 meV gives the 2s-exciton homogeneous linewidth governed by elastic scattering into the hot 1s exciton states.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 23
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 17 (1995), S. 1277-1284 
    ISSN: 0392-6737
    Keywords: II–IV semiconductors ; Excitons and related phenomena (including electron-hole drops) ; Time-resolved optical spectroscopies and other ultrafast optical measurements in condensed matter ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary Steady-state and picosecond photoluminescence experiments on CdTe/CdZnTe and CdTe/CdMnTe asymmetric double quantum wells are presented. An external magnetic field is used to tune the coupling between the two QWs by allowing resonances to occur between excitonic states. Very efficient tunnelling is found when an exciton from the high-energy QW can transfer either with the emission of an LO phonon or via the resonance with the 2s state of the low-energy QW.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 24
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 17 (1995), S. 1339-1342 
    ISSN: 0392-6737
    Keywords: Excitons and related phenomena (including electron-hole drops) ; Time resolved optical spectroscopies and other ultrafast optical measurements in condensed matter ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary Fast initial decays of both the luminescence intensity and the circular luminescence polarization at high exciton densities, under resonant excitation, are reported for the first time. These fast decays are simultaneously initiated by the increase of the ellipticity of the photogenerating picosecond laser beam. The theory of the mechanism illustrates the driving role of the interexciton exchange interaction.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 25
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 17 (1995), S. 1389-1393 
    ISSN: 0392-6737
    Keywords: Excitons and related phenomena (including electron-hole drops) ; Surface and interface electron states ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary We calculated the energy and the wave function of the exciton for i) a V-shaped quantum wire, ii) a T-shaped quantum wire and iii) a quantum wire resulting from strain-induced lateral confinement. The full Luttinger and Bir-Pikus Hamiltonian are taken into account in the three calculations. We used different parameters inside the well and at the barrier. The basis states |3/2m〉 are defined with respect to [110], the direction of the wire in the three kinds of structures, instead of the usual [001] direction. The hole dispersion curve allows one to define an effective mass which is to be introduced in the variational calculation of the exciton binding energy. We show that the hole is confined in a wire only in case i).
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 26
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 17 (1995), S. 1413-1416 
    ISSN: 0392-6737
    Keywords: Excitons and related phenomena (including electron-hole drops) ; Surface and interface electron states ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary An opening (antidot) in two-dimensional (2D) electron gas placed in a strong perpendicular magnetic field makes it possible the formation of ring-shaped excitons stemming from the skipping-states of electrons and holes. The binding energy of the ground state of such excitons is logarithmically larger than that of the «bulk» 2D excitons. The possibility of tunnelling electron to hole (or vice versa) around the antidot results in a shift for each of the excitons levels that oscillates with the magnetic field.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 27
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 17 (1995), S. 1359-1366 
    ISSN: 0392-6737
    Keywords: Optical transient phenomena (including quantum beats, dephasings and revivals, photon echoes, free induction decay, and optical mutation) ; Excitons and related phenomena (including electron-hole drops) ; Electron states in low-dimensional structures (including quantum wells, superlattices, layer structures, and intercalation compounds) ; Weak localization effects (e.g., quantized states) ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary The optical properties of multiple quantum wells in the transition from isolated wells to a superlattice are investigated theoretically and experimentally. For superlattices with a miniband width similar to the binding energy of the 2s exciton of the isolated quantum well we find an exciton state energetically between the 1s exciton state and the onset of the miniband absorption. We find this state to be an interwell exciton, with the electron confined to one well and the hole to the neighboring well. The interwell exciton resembles the first Wannier-Stark localized exciton of a biased superlattice. However, the localization in the present case is mediated by the Coulomb interaction of the electron and hole. The state has considerable oscillator strength and is observed experimentally in linear and nonlinear experiments.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 28
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 17 (1995), S. 1395-1400 
    ISSN: 0392-6737
    Keywords: Excitons and related phenomena (including electron-hole drops) ; Tunneling ; Other semiconductor-to-semiconductor contacts,p-n junctions, and heterojunctions ; Electroluminescence ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary The electroluminescence of p-i-n GaAs double-barrier resonant tunnelling diodes has been investigated for various concentrations of free carriers (either holes or electrons) in the quantum well (QW). For these structures it is possible to change the relative electron or hole density quasi-continuously with applied bias-voltage. New low-temperature excitonic recombinations are identified in the electroluminescence spectra. Continuous variation of the carrier density in the quantum well from a hole-rich into an electron-rich environment leads to the observation of positively charged excitons (X 2 +), neutral excitons (X), negatively charged excitons (X −) and finally an unbound electron-hole recombination. An increased temperature causes the dissociation of the charged excitons in favour of the neutral heavy-hole free excitonX. In high magnetic fields the unbound electron-hole recombination is transferred into an excitonic recombination.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 29
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 17 (1995), S. 1417-1422 
    ISSN: 0392-6737
    Keywords: Polaritons (including photon-phonon and photon-magnon interactions) ; Excitons and related phenomena (including electron-hole drops) ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary The excitonic energies are computed in superlattices from the poles in the imaginary part of the susceptibility, using an appropriate Green's function expression for the coherent amplitude function of the electron-hole pair. Solving the Maxwell equations, the polariton states are obtained and the optical properties are computed. The procedure includes the effects of coherence between the carriers and the electromagnetic field, and it does not require any type of additional boundary conditions. Detailed calculations in GaAs/Ga1−x Al x As superlattices show polaritonic effects in the optical properties, in particular a peculiar fine-structure lineshape of then=1 andn=2 hh and lh excitons is obtained. A comparison with similar calculations in bulk GaAs clearly shows the roles of quantum confinement and of anisotropy in the superlattice.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 30
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 17 (1995), S. 1441-1446 
    ISSN: 0392-6737
    Keywords: Excitons and related phenomena (including electron-hole drops) ; Polaritons (including photon-phonon and photon-magnon interactions) ; Optical properties of thin films, surfaces, and layer structures (superlattices, heterojunctions, and multilayers) ; II–VI compounds and other chalcogenides ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary Experimental studies of high-resolution reflectivity and a temperature dependence of the photoluminescence for periodic MQWs of CdTe/CdZnTe with periods equal to a one-half and one-forth of the light wavelength are presented. Energies and radiative lifetimes of the polariton-like excitations in the relevant structures are computed, and linked to experimental observations.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 31
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 17 (1995), S. 1465-1471 
    ISSN: 0392-6737
    Keywords: Surface and interface electron states ; Excitons and related phenomena (including electron-hole drops) ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary The localization of the wave function on the scale length of a single monolayer has been studied by magnetophotoluminescence in GaSb/AlGaSb quantum wells. The studied range of well width includes the direct-indirect transition involvingL-point conduction states and Γ-point valence states induced by quantum size effects. Separate carrier localization dominates at higher field values (B〉2T), whereas the excitonic effects are important only in the low field range. Variational calculations of the excitonic transverse extension provide a quantitative description of the experimental data. The dependence of the effective reduced mass on the well width has been obtained experimentally by magnetoluminescence that is highly sensitive to the modifications of the wave function, even on the scale of a single monolayer.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 32
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 17 (1995), S. 1505-1508 
    ISSN: 0392-6737
    Keywords: Excitons and related phenomena (including electron-hole drops) ; Electron states in low-dimensional structures (including quantum wells, superlattices, layer structures, and intercalation compounds) ; III-V and II-VI inorganics ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary A model for calculating exciton binding energies in quantum wells (QWs) is presented, which can be applied to situations in which one of the two band discontinuities is large, while the second one can be arbitrary (positive, negative, or zero). The model is applied to ZnSe/ZnSSe and InGaAs/GaAs QWs., The crossover between strong-and weak-confinement, regimes for excitons in narrow QWs is studied within a simplified model with two one-parameter, variational wave functions.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 33
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 17 (1995), S. 1549-1553 
    ISSN: 0392-6737
    Keywords: Studies of specific magnetic materials ; Excitons and related phenomena (including electron-hole drops) ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary The influence of the electron spin splitting on the stability of quasi-two-dimensional donor bound excitons (D 0 X) has been investigated in the Cd0.97Mn0.03Te/Cd0.7Mg0.3Te semi-magnetic semiconductor quantum well (QW) structure. TheD 0 X binding energy has been measured directly from emission spectra recorded at magnetic field parallel to the QW plane. Complexes have been shown to dissociate into a neutral donor and a free exciton with a spin flip of the electron at high magnetic fields when the electron spin splitting exceeds the binding energy.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 34
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 17 (1995), S. 1629-1633 
    ISSN: 0392-6737
    Keywords: III–V semiconductors ; Excitons and related phenomena (including electron-hole drops) ; III–V compounds and systems ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary We report on the biexciton formation of the pseudodirect exciton consisting of the AlAs-X z electron and the GaAs-Γ heavy hole in (GaAs) m /(AlAs) m type-II superlattices withm=10, 12, and 13 monolayers. The photoluminescence lineshape of the pseudodirect exciton exhibits a doublet feature having an energy separation of ∼3 meV at the excitation power of the order of mW/cm2 in all the samples, and the low-energy band grows superlinearly. The transient profiles of the doublet photoluminescence band early indicate the biexciton formation: the delay of the rise of the biexciton photoluminescence on the low-energy side and its shorter decay time in comparison with the exciton photoluminescence.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 35
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 17 (1995), S. 1487-1492 
    ISSN: 0392-6737
    Keywords: III-V semiconductors ; Electron states in low-dimensional structures (including, quantum wells, superlattices, layer structures, and intercalation compounds) ; Excitons and related phenomena (including electron-hole drops) ; Brillouin and Rayleigh scattering ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary A detailed study of the relative role played by localized and/or propagating intermediate excitonic states in, resonant Rayleigh scattering (RRS) is presented for a large set of GaAs quantum well (QW) and bulk structures. We show that the two kinds of states contribute to RRS through different mechanisms. We concluded that RRS occurs via localized states in QW heterostructures, very likely due to localization by the interface roughness, while bulk, crystals turn out to be better candidates for RRS via propagating states.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 36
    ISSN: 0392-6737
    Keywords: Surface and interface electron states ; Excitons and related phenomena (including electron-hole drops) ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary Quantum wire heterostructures, such as V- and T-shaped wires, are very promising candidates for low-threshold lasing. A crucial issue is the excitonicvs. free-carrier nature of the radiative recombination. Here, we report on magnetophotoluminescence studies of GaAs and InGaAs V-shaped wires that allow to discriminate different regimes of radiative recombination.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 37
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 17 (1995), S. 1601-1605 
    ISSN: 0392-6737
    Keywords: Excitons and related phenomena (including electron-hole drops) ; Polaritons (including photon-phonon and photon-magnon interactions) ; Time-resolved optical spectroscopies and other ultrafast optical measurements in condensed matter ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary Low-temperature time-resolved luminescence experiments with picosecond resolution have been performed on excitons in a microcavity containing InGaAs quantum wells. The decay curves are very dependent on the energy difference between the cavity mode and the exciton. They agree qualitatively with a model which takes into account a reservoir at the exciton energy and two splitted radiant states.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 38
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 17 (1995), S. 1613-1617 
    ISSN: 0392-6737
    Keywords: Excitons and related phenomena (including electron-hole drops) ; Optical properties of thin films surfaces and layer structures (superlattices, heterojunctions and multilayers) ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary We present an analysis of the inter- and intrasubband relaxation dynamics of excitons due to Fröhlich coupling in an unbiased asymmetric double quantum well made from CdTe/CdMnTe. We consider the relaxation processes that take place in the time interval between the excitation of the lowest exciton localized in the narrow well and the recombination in the wide well, by means of Fermi's golden rule. As the excitation falls in the range of a Fano resonance, we have to employ an extended set of rate equations to incorporate the effect of the continuum of initially populated states. Thus, we obtain the transient luminescence, which can directly be compared with time-resolved luminescence experiments.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 39
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 17 (1995), S. 1663-1667 
    ISSN: 0392-6737
    Keywords: Excitons and related phenomena (including electron-hole drops) ; III–V semiconductors ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary We calculate scattering rates of QW excitons by acoustic phonons using realistic deformation potentials for electrons and holes in structures based on GaAs. We use these rates in order to reproduce the exciton dynamics in a time-resolved photoluminescence experiment. Rise time and decay time of the luminescence signal are studied as a function of temperature and QW size. The exciton distribution function reaches a stationaryshape after the luminescence passes through its maximum. This shape shows strong deviations from the thermalequilibrium distribution, at least for temperatures below 50 K. As a consequence, exciton radiative recombination is slower than the usually expected thermal average of the radiative rate. We discuss the dependence of this effect on the well width.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 40
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 17 (1995), S. 1769-1774 
    ISSN: 0392-6737
    Keywords: Optical transient phenomena (including quantum beats, dephasings and revivals, photon echoes, free induction decay, and optical nutation) ; Excitons and related phenomena (including electron-hole drops) ; Electron states in low-dimensional structures (including quantum wells, superlattices, layer structures, and intercalation compounds) ; Time-resolved optical spectroscopies and other ultrafast optical measurements in condensed matter ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary We have studied experimentally the coherent exciton-photon dynamics in a single, a double, and a quintuple quantum well structure under resonant excitation. In pump and probe experiments we observe an initial fast decay of the exciton population. This initial decay depends on the number of quantum wells. The population decay is accompanied by a coherent light emission induced by the first-order polarization, the intensity of which increases quadratically with the quantum well number. Interference effects and electromagnetic coupling effects between polarizations located in distinct quantum wells probably play a crucial role in the superlinear coherent emission process.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 41
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 17 (1995), S. 1295-1303 
    ISSN: 0392-6737
    Keywords: Polaritons (including photon-phonon and photon-magnon interactions) ; Excitons and related phenomena (including electron-hole drops) ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary We have investigated the dynamics of impulsively excited planar microcavities in the strongly couple regime. With resonant, coherent excitation, the emitted light shows vacuum-Rabi oscillations and a lifetime corresponding to twice the cavity lifetime. As the light intensity is increased, the exciton bleaching leads to reduced normal-mode splitting. The role of interface disorder on the dynamic splitting is discussed. Coherence transfer in exciton-exciton scattering is observed. Off-resonant excitation leads to long lifetimes limited by scattering into the radiatively coupled states of the exciton-cavity system.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 42
    ISSN: 0392-6737
    Keywords: Excitons and related phenomena (including electron-hole drops) ; II–VI semiconductors ; Wave propagation, transmission and absorption ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary The spectra of transmission and reflection of synthetic opal which has 3-dimensional periodic structure were measured at different orientations of incident beam relative to the sample facets. It is shown that opal behaves as «semi-metallic» photonic band gap (PBG) material in the vicinity of photon energy 2.3 eV. The synthesis of CdS microcrystals embedded in the pores of opal was made for the first time in an attempt to form a system of quantum dots. Optical spectra (reflection and transmission, photoluminescence and Raman scattering) were studied. The results demonstrate good crystallinity of microcrystals embedded in opal matrix and exhibit well-pronounced quantum confinement effects in fundamental edge absorption spectra. The spectral overlap of the PBG of opal with electronic band gap of many of II–VI semiconductors seems to make opal/semiconductor system a promising media for experimental studies of such PBG-related effects as inhibition of spontaneous emission, microcavity polariton, etc.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 43
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 17 (1995), S. 1377-1382 
    ISSN: 0392-6737
    Keywords: Excitons and related phenomena (including electron-hole drops) ; Time-resolved optical spectroscopies and other ultrafast optical measurements in condensed matter ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary The influence of biexciton formation on the four-wave-mixing response of multiple quantum wells having a strong inhomogeneous broadening of the exciton transitions has been investigated. The experimental results are consistent with a model which distinguishes between crystal regions where the exciton energy is almost constant over the spatial extension of the biexciton state, and regions where the fluctuations of the exciton energy are comparable to or larger than the biexciton binding energy.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 44
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 17 (1995), S. 1459-1463 
    ISSN: 0392-6737
    Keywords: Excitons and related phenomena (including electron-hole drops) ; Other luminescence and radiative recombination ; Structural modeling: serial-addition models, computer simulation ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary We have observed an anomaly in the low-temperature photoluminescence of dipole-oriented long-lived excitons in a coupled quantum well under an electrical bias. A discrepancy between the experiment and a Monte Carlo simulation for the exciton diffusion in the system suggests a boson correlation for a two-dimensional Bose system in a random potential with repulsive interaction between bosons.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 45
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 17 (1995), S. 1481-1486 
    ISSN: 0392-6737
    Keywords: Excitons and related phenomena (including electron-hole drops) ; Electron states in low-dimensional structures (including quantum wells, superlattices, layers structures, and intercalation compounds) ; Optical properties of thin films, surfaces, and layer structures (superlattices, heterojunctions, and multilayers) ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary We report experimental results on photoluminescence and excitation of photoluminescence of GaAs/Ga0.7Al0.3As quantum wells (19, 38.5 and 77 Å) grown on nominal and vicinal GaAs substrates. In order to study the influence of the interface microscopic structure on the optical properties of the studied quantum wells, we perform luminescence experiments at low temperature by exciting selectively a small area of a few μm2. In this way the presence of isolated islands on the interface is evidenced by a fine structure in the photoluminescence and photoluminescence excitation spectra. The difference in localization length of excitons in samples with steps along the [110] and the [110] directions is emphasized.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 46
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 17 (1995), S. 1669-1673 
    ISSN: 0392-6737
    Keywords: Excitons and related phenomena (including electron-hole drops) ; Quantum Hall effect (including fractional) ; III–V semiconductors ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary Energy spectrum of an exciton and electron density distribution in it under the fractional quantum Hall regime are calculated within the framework of an anyon exciton model.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 47
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 17 (1995), S. 1211-1218 
    ISSN: 0392-6737
    Keywords: Polaritons (including photon-phonon and photon-magnon interactions) ; Electrons states in low-dimensional structures (including quantum wells, superlattices, layer structures, and intercalation compounds) ; III–V and II–VI inorganics ; Excitons and related phenomena (including electron-hole drops) ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary A description of polariton effects on excitons in multiple quantum wells (MQWs), superlattices (SLs), and semiconductor microvavities is presented. The non-local semi-classical theory in a transfer matrix formulation is adopted. The radiative width in MQWs atk=0 increases first with the number of wellsN, then goes to zero asN→∞, where stationary SL polaritons are recovered. The crossover from weak- to strong-coupling regimes for QW excitons in microcavities is described. The complex energies of the mixed exciton-radiation modes are shown to be measurable by time-resolved transmission experiments.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 48
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 17 (1995), S. 1219-1228 
    ISSN: 0392-6737
    Keywords: Excitons and related phenomena (including electron-hole drops) ; Electron states in low-dimensional structures (including quantum wells, superlattices, layer structures, and intercalation compounds) ; Optical properties of thin films surfaces and layer structures (superlattices, heterojunctions and multilayers) ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary We present a comprehensive discussion of the excitonic properties of V-shaped GaAs and InGaAs quantum wires grown on patterned substrates. Systematic linear and non-linear spectroscopic studies have been performed in order to clarify the impact of lateral confinement on the exciton wave function, namely: enhanced exciton binding energy, localization in magnetic field, recombination from excited states and multiphoton absorption. The careful evaluation of the electron confinement energies, based on the actual quantum wire profile obtained by TEM micrographs, including the internal piezoelectric field induced by off-diagnoal terms of strain tensor, reproduces quite well the measured one-dimensional states. Finally, application of quantum wires in a p-i-n wave guide for bistable operation is demonstrated.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 49
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 17 (1995), S. 1651-1656 
    ISSN: 0392-6737
    Keywords: Excitons and related phenomena (including electron-hole drops) ; Polaritons (including photon-phonon and photon-magnon interactions) ; III–V semiconductors ; Cooperative phenomena ; superradiance and superfluorescence ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary We study excitons in double quantum wells (DQWs) embedded in a semiconductor microcavity (MC) by means of semi-classical theory, which yields analytic results in weak- and strong-coupling regimes. We show how to obtain subpicosecond radiative lifetime for the excitons. A model for disorder is investigated.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 50
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 17 (1995), S. 1675-1680 
    ISSN: 0392-6737
    Keywords: Excitons and related phenomena (including electron-hole drops) ; Electron states in low-dimensional structures (including quantum wells, superlattices, layer structures, and intercalation compounds) ; II–VI semiconductors ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary We discuss the exciton centre-of-mass dispersion in a (Ga,Al)As-GaAs-AlAs-(Ga, Al)As quantum well taking into account the Γ-X coupling. The position of the Γ andX quantum well levels is monitored by applying an external electric field. Near the degeneracy, the coupling plays an important role mixing the Γ andX levels. As a consequence, the exciton in-plane mass presents a significant non-parabolicity as its values change from a Γ-reduced mass to aX-reduced mass.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 51
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 17 (1995), S. 1229-1237 
    ISSN: 0392-6737
    Keywords: Excitons and related phenomena (including electron-hole drops) ; Electron states in low-dimensional structures (including quantum wells, superlattices, layer structures, and intercalation compounds) ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary We consider in this work the scattering of low-energy excitons in single quantum wells. In the first part we consider the elastic scattering by a static centre (charged impurity) and discuss the validity of the first Born approximation, which is expected to work well only for particles with large kinetic energy. The second part is devoted to the inelastic scatterings of individual excitons by a phonon reservoir. We discuss in particular the validity of the elastic approximation, which is well known to be very accurate for particles with large kinetic energy.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 52
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 17 (1995), S. 1239-1245 
    ISSN: 0392-6737
    Keywords: Excitons and related phenomena (including electron-hole drops) ; III–V semiconductors ; Photoluminescence ; Metal-insulator transitions ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary We implement optical spectroscopy to study charged excitons (trions) in modulation-doped GaAs/AlGaAs quantum wells. We observe for the first time several new trions: the positively charged exciton, the light-hole negatively charged exciton and the triplet state of the negatively charged exciton.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 53
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 17 (1995), S. 1713-1716 
    ISSN: 0392-6737
    Keywords: Polaritons (including photon-phonon and photon-magnon interactions) ; Electron states in low-dimensional structures (including quantum wells, superlattices, layer structures, and intercalation compounds) ; III–V and II–VI inorganics ; Excitons and related phenomena (including electron-hole drops) ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary A quantum-mechanical model for quantum well polaritons in semiconductor microcavities is presented. The real and imaginary parts of the polariton dispersion are obtained. They represent, respectively, the position and the linewidth of the luminescence peaks observed in typical experiments. The model includes the features of the distributed Bragg reflectors which constitute the cavity mirrors, and has the advantage of describing the weak-coupling as well as the strong-coupling regimes characteristic of this kind of systems. Furthermore, in the limit where no cavity is present, the well-known result for quantum well polaritons is recovered.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 54
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 17 (1995), S. 1735-1741 
    ISSN: 0392-6737
    Keywords: Wave propagation, transmission and absorption ; Optical properties of thin films, surfaces and layer structures (superlattices, heterojunctions, and multilayers) ; Excitons and related phenomena (including electron-hole drops) ; Time-resolved optical spectroscopies and other ultrafast optical measurements in condensed matter
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary It is shown that collective effects determine the optical response of radiatively coupled multiple-quantum-well structures. Stimulated decay of the coherent electronic excitations is predicted for systems where the periodicity unit is an integer multiple of half the optical wavelength. For quarter wavelength structures it is shown that the induced optical coupling causes an interwell energy transport and a splitting of the excitonic resonances leading to quantum beats in the time-resolved transmitted and reflected signal.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 55
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 17 (1995), S. 1759-1762 
    ISSN: 0392-6737
    Keywords: Optical transient phenomena (including quantum beats, dephasings and revivals, photon echoes, free induction decay, and optical mutation) ; Excitons and related phenomena (including electron-hole drops) ; Time-resolved optical spectroscopies and other ultrafast optical measurements in condensed matter ; Optical properties of thin films, surfaces and thin layer structures (including superlattices, heterostructures, and intercalation compounds) ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary We study exciton ionization induced by an axial electric field in a strongly coupled GaAs/Al0.3 Ga0.7 As superlattice at low temperatures. The field-induced ionization times of the heavy-hole 1s exciton in the miniband field regime are determined from transient four-wave-mixing experiments and theoretical model calculations. They are found to lie between the field ionization times of excitons in bulk semiconductors, and in strongly confined quantum well systems.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 56
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 61 (1995), S. 467-474 
    ISSN: 1432-0630
    Keywords: 73.20.-r ; 73.20.Dx ; 61.16.Ch
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract It is shown how wire structures a few nanometers wide can be fabricated by decorating step edges at vicinal surfaces. Their growth modes and electronic states are studied using Scanning Tunneling Microscopy (STM) and inverse photoemission. The observed growth modes are two-dimensional analogs of Stranski-Krastanov growth and layer-by-layer growth in three dimensions, e.g., for Cu on stepped Mo(1 1 0) and W(1 1 0), respectively. Contrast between different metals is achieved in STM pictures by resonant tunneling via surface states and image states, with the latter providing a map of the work function. The limit of single atomic rows decorating step edges is studied by inverse photoemission, and an energy shift of 0.4 eV is found for electronic states of step atoms. We expect stripe structures to become useful for the study of two- vs one-dimensional magnetism, for magnetoresistive films, and in the design of anisotropic materials.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 57
    ISSN: 1432-0630
    Keywords: 73.20.Dx ; 13.40. DK
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Analytical expressions for the transmission coefficient and the resonance condition in unsymmetrical rectangular double-barrier structures are derived theoretically by taking into account the mass difference between well and barrier layers. It is found that resonant tunneling with a transmission peak equal to 1 (unity resonance) and resonant tunneling with a transmission peak less than 1 (below unity resonance) may occur in the unsymmetrical double-barrier structures. Two independent conditions are required for unity-resonant transmission: One is the Phase-Difference Condition for Resonance (PDCR) and the other is the Maximum Condition for the Peak Value (MCPV). The below-unity resonant transmission occurs when only condition PDCR holds. It is believed that the two conditions are useful for calculating values of the transmission coefficient and the resonance energy for the unsymmetrical double-barrier structures. They may be useful for resonant tunneling-device fabrication. Furthermore, wave functions of an electron at resonance level are calculated and the confining phenomenon is confirmed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 58
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 18 (1996), S. 747-752 
    ISSN: 0392-6737
    Keywords: Polarons and electron-phonon interactions ; Excitons and related phenomena (including electron-hole drops)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary The polaron effect on the binding energy of a hydrogenic impurity in a semiconductor quantum well is calculated by a variational approach taking into account the quasi-two-dimensional and the realist structures of systems. For the finite potential barrier, a correction is obtained as a function of the well thickness and presents a maximum; its evolution is analogous to the binding energy.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 59
    Electronic Resource
    Electronic Resource
    Springer
    JETP letters 65 (1997), S. 484-490 
    ISSN: 1090-6487
    Keywords: 73.40.Gk ; 73.20.Dx ; 72.15.Eb ; 71.20.Be
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A new mechanism is proposed for the anomalous tunneling transmittance of a double-barrier quantum-well structure doped with a transition-metal impurity and possessing an intrinsic two-dimensional continuum. The new tunneling channels are due to exponentially-narrow single-particle resonances arising near the edge of a 2D band during tunneling. They are temperature-independent and their contribution to the transmittance can exceed the contribution of the Kondo resonance even at temperatures T〈T K .
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 60
    ISSN: 1090-6487
    Keywords: 73.40.Kp ; 73.20.Dx
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Electron transport through an asymmetric heterostructure with a two-step barrier N+GaAs/N−GaAs/Al0.4Ga0.6As/Al0.03Ga0.97As/N−GaAs/N+GaAs was investigated. Features due to resonance tunneling both through a size-quantization level in a triangular quantum well, induced by an external electric field in the region of the bottom step of the barrier (Al0.03Ga0.97As layer), and through virtual levels in two quantum pseudowells of different width are observed in the tunneling current. The virtual levels form above the bottom step or above one of the spacers (N−GaAs layer) as a result of interference of electrons, in the first case on account of reflection from the Al0.4Ga0.6As barrier and a potential jump at the Al0.03Ga0.97As/N−GaAs interface and in the second case — from the Al0.4Ga0.6As barrier and the potential gradient at the N−GaAs/N+GaAs junction, reflection from which is likewise coherent.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 61
    Electronic Resource
    Electronic Resource
    Springer
    JETP letters 67 (1998), S. 196-202 
    ISSN: 1090-6487
    Keywords: 73.20.Dx ; 73.23.Hk
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A model is found whereby the Coulomb interaction during electron transport in quantum wires of finite length with current-lead contacts can be taken into account exactly (within the framework of the bosonization method). It is established that the charge density distribution along a wire in the case of the real Coulomb interaction is strongly different from the Luttinger liquid model, where the interaction is assumed to be short-ranged. The charge density near the contacts is found to be much higher than in the model with a short-range interaction, but away from the contacts the two densities are closer to each other.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 62
    ISSN: 1090-6487
    Keywords: 42.55.Px ; 73.20.Dx
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A solution of the nonstationary Schrödinger equation describing the resonance interaction of electrons with a weak rf field is found for asymmetric triple-barrier resonance-tunneling structures with thin, high barriers, and an expression is obtained for the active weak-signal conductivity of such structures. It is found that in a number of cases the probability of quantum resonance transitions from an upper to a lower level can increase sharply when the lower levels are shifted relative to one another.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 63
    Electronic Resource
    Electronic Resource
    Springer
    JETP letters 68 (1998), S. 915-921 
    ISSN: 1090-6487
    Keywords: 73.20.Dx ; 73.61.−r
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract It is found that various kinds of shell structure which occur at specific values of the magnetic field lead to the disappearance of the orbital magnetization for particular magic numbers in small quantum dots with electron number A〈30.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 64
    ISSN: 1090-6487
    Keywords: 81.15.Hi ; 73.20.Dx ; 68.65.+g
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The characteristic features of electronic spectra in Ge/Si (100) heterostructures obtained by molecular-beam epitaxy are investigated by capacitance spectroscopy. It is observed that the self-organization of a Ge film into an island film when the effective germanium thickness exceeds six monolayers is accompanied by the appearance of hole bound states, which can be attributed to size quantization and the Coulomb interaction of carriers in the array of Ge quantum dots.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 65
    Electronic Resource
    Electronic Resource
    Springer
    JETP letters 68 (1998), S. 673-678 
    ISSN: 1090-6487
    Keywords: 74.20.−z ; 73.20.Dx ; 74.25.Ha ; 11.30.Pb
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract In the theory of mesoscopic superconductivity it is necessary to supplement the coordinates x, y, z with some additional physical characteristics (coordinates) of free space. An adequate description of mesoscopic superconductivity is obtained by introducing a nonrelativistic version of Grassmann spinor coordinates, which are studied in supersymmetric field theories and convert ordinary space into superspace. An experimental check of the proposed description of the superconducting and magnetic properties of metallic nanoparticles would provide a direct confirmation of the concept of superspace.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 66
    ISSN: 1090-6487
    Keywords: 73.20.Dx ; 73.40.Hm ; 84.37.+q
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract It is shown that capacitance spectroscopy can be used to investigate the spin polarization of two-dimensional electronic systems (2DESs). We employed this method to investigate the spin polarization of 2DESs in a GaAs/AlGaAs heterojunction for filling factors of the magneticquantization levels 0.28〈ν〈0.9. It is proved that in the presence of states of the fractional quantum Hall effect with ν f =1/3 and 2/3 the ground state of a 2DES with ν〉2/3 is incompletely spin-polarized.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 67
    ISSN: 1090-6487
    Keywords: 73.20.Dx ; 71.35.−y ; 33.15.Pw
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The experimental results of a study of the fine structure of the levels of excitons localized in InAlAs quantum dots in an AlGaAs matrix are reported. Transformations from optical orientation to alignment and from alignment to orientation, which occur due to the exchange splitting of a dipole-active excitonic doublet and are allowed by the low symmetry of a quantum dot, are observed in a longitudinal magnetic field (Faraday geometry). A comparison of theory with experiment for a self-organized ensemble of quantum dots enables a determination of the character of the distribution over the dipole orientations for resonance optical transitions.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 68
    ISSN: 1090-6487
    Keywords: 73.20.Mf ; 73.20.Dx ; 78.55.Cr
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Photoluminescence spectra of interwell excitons in double GaAs/AlGaAs quantum wells (n-i-n structures) have been investigated (an interwell exciton in these systems is an electron-hole pair spatially separated by a narrow AlAs barrier). Under resonance excitation by circularly polarized light, the luminescence line of interwell excitons exhibits a significant narrowing and a drastic increase in the degree of circular polarization of photoluminescence with increasing exciton concentration. It is found that the radiative recombination rate significantly increases under these conditions. This phenomenon is observed at temperatures lower than the critical point and can be interpreted in terms of the collective behavior of interwell excitons.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 69
    Electronic Resource
    Electronic Resource
    Springer
    JETP letters 71 (2000), S. 391-394 
    ISSN: 1090-6487
    Keywords: 73.20.Dx ; 03.65.−w
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The two-electron dynamics in a symmetric double quantum dot placed in a onstant electric field is considered. It is shown that, despite the Coulomb blockade, interdot electron-density oscillations are possible. In these oscillations, a charge equal to the charge of a single electron is periodically transferred from one quantum dot to the other.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 70
    Electronic Resource
    Electronic Resource
    Springer
    JETP letters 65 (1997), S. 253-258 
    ISSN: 1090-6487
    Keywords: 71.45.Gm ; 73.20.Dx ; 73.40.Lq
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract It is shown that the phase transition of density-wave origin in homogeneous liquids is preceded by fermion condensation. Thus fermion condensation may be observed in low-density electron liquids, neutron stars, and liquid He3. Three-dimensional (3D) and two-dimensional (2D) liquids are considered.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 71
    Electronic Resource
    Electronic Resource
    Springer
    JETP letters 68 (1998), S. 669-672 
    ISSN: 1090-6487
    Keywords: 71.35.Ji ; 73.20.Dx
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The ground state of a spatially indirect exciton in type-II quantum dots with a short-range potential acquires nonzero angular momentum in the presence of a magnetic field oriented perpendicular to the plane of the system. The critical magnetic field of the transition to a ground state with nonzero angular momentum depends on the radius of the quantum dot. Such a transition can be observed as quenching of luminescence by a magnetic field in quantum dots of the GaSb/GaAs system, for example.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 72
    Electronic Resource
    Electronic Resource
    Springer
    JETP letters 66 (1997), S. 431-436 
    ISSN: 1090-6487
    Keywords: 72.20.My ; 73.20.Dx
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A study is made of the four-terminal Hall junction under the influence of a radiation field. The frequency of the radiation field is tuned to a transition between the energy of a bound state below a conduction subband and the Fermi energy of the incident electrons. Radiation-field-induced resonant dips of the Hall resistance are exhibited at low magnetic fields.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 73
    ISSN: 1090-6487
    Keywords: 85.30.Vw ; 73.20.Dx ; 78.30.Fs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The spontaneous emission of far-infrared radiation (λ≅10–20 μm) from diode structures with vertically coupled InGaAs/AlGaAs quantum dots is observed. This emission is due both to transitions of holes and electrons between size-quantization levels in quantum dots and to transitions from the continuum to a level in a quantum dot. It is observed only when accompanied by lasing at short wavelengths (λ≅0.94 μm) and, like the short-wavelength emission, it exhibits a current threshold. The spontaneous emission of long-wavelength radiation is also observed in InGaAs/GaAs quantum-well laser structures. This radiation is approximately an order of magnitude weaker than that from quantum-dot structures, and it has no current threshold.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 74
    Electronic Resource
    Electronic Resource
    Springer
    JETP letters 67 (1998), S. 1069-1075 
    ISSN: 1090-6487
    Keywords: 71.10.Hf ; 71.27.+a ; 73.20.Dx
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract It is shown that additional scattering due to tunneling induces a transition of the system from a non-Fermi-liquid into a Fermi-liquid state as the distance between the Fermi level in the walls and the 2D-band edge is varied in a double-barrier quantum well, doped with transition-metal impurities and having an intrinsic two-dimensional continuum.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 75
    ISSN: 1090-6487
    Keywords: 75.60.Nt ; 75.60.Ch ; 75.70.Cn ; 73.20.Dx
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract It is shown that under resonance tunneling conditions the energy structure of electric-field domains in doped superlattices is substantially different from a resonance structure. As the impurity concentration decreases, the domain walls become wider and the current hysteresis becomes narrower (collapses) as a result of the mismatch of the resonance levels in the region of a domain wall. A physical interpretation of the criterion for the existence of electric-field domains is given.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 76
    ISSN: 1090-6487
    Keywords: 73.40.Hm ; 72.15.−v ; 73.20.Dx
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The effect of the nuclear hyperfine interaction on the dc conductivity of 2D electrons under quantum Hall effect conditions at filling factor ν=1 is observed for the first time. The local hyperfine field enhanced by dynamic nuclear polarization is monitored via the Overhauser shift of the 2D conduction electron spin resonance in AlGaAs/GaAs multiquantum-well samples. The experimentally observed change in the dc conductivity resulting from dynamic nuclear polarization is in agreement with a thermal activation model incorporating the Zeeman energy change due to the hyperfine interaction. The relaxation decay time of the dc conductivity is, within experimental error, the same as the relaxation time of the nuclear spin polarization determined from the Overhauser shift. These findings unequivocally establish the nuclear spin origins of the observed conductivity change.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 77
    ISSN: 1090-6487
    Keywords: 73.20.Dx ; 73.20.Hb
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A radical change in the ionization energy of the donor impurity Si in a GaAs/AlGaAs double-well heterostructure is observed experimentally when the electronic wave function is relocated in an electric field. The ionization energy of the impurity decreases from 15.5 meV to 0 when the voltage across the structure changes by less than 1 V. The Stark effect would give a change in the ionization energy of not more than 3 meV.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 78
    Electronic Resource
    Electronic Resource
    Springer
    JETP letters 69 (1999), S. 250-254 
    ISSN: 1090-6487
    Keywords: 73.20.Dx ; 61.46.+w
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A study is made of the Förster energy transfer from an excited semiconductor quantum dot to an organic material surrounding the dot. A quantum-mechanical microscopic description of a Wannier-Mott exciton in a quantum dot is employed together with a macroscopic description of the organic medium. The calculations show that for II–VI semiconductors such transfer can occur in a time of the order of tens of picoseconds, which is much shorter than the lifetime of an excitation in a quantum dot in the absence of transfer. Therefore, just as for quantum wells, the energy transfer mechanism considered can be a quite efficient means for pumping organic sources of radiation.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 79
    Electronic Resource
    Electronic Resource
    Springer
    JETP letters 64 (1996), S. 460-466 
    ISSN: 1090-6487
    Keywords: 73.20.Dx ; 76.40.+b
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A number of effects associated with the curvature of the surface on which a two-dimensional (2D) electron gas is placed are studied. The most significant effect in an external magnetic field (which for 2D electrons becomes effectively nonuniform) is the lifting of the degeneracy of the Landau levels. The intensity and shape of the cyclotron resonance line (inhomogeneously broadened) for different polarizations and the corrections to the Hall constant are found for the example of a circular cylinder. A picture of the quantization of the conductance that is qualitatively different from the case of a flat strip is obtained for a quasi-one-dimensional quantum wire in the form of a hollow cylinder. It is shown that in contradistinction to the planar case the spectrum of 2D electrons on the curved surface is sensitive to the sign of the spin-orbit coupling constant (for a fixed sign of the curvature). For hetero-junctions, for example, this opens up new possibilities for extracting information about their “hidden parameters.”
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 80
    Electronic Resource
    Electronic Resource
    Springer
    JETP letters 64 (1996), S. 592-600 
    ISSN: 1090-6487
    Keywords: 72.90.+y ; 73.20.Dx ; 73.40.−c ; 73.90.−f
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Macroscopic charge quantization is analyzed in the case in which thermal activation across trapping barriers dominates over tunneling and the barrier heights are comparable to the charging and thermal energies. Barrier suppression, the image force due to the finite electron charge, and the contribution of unstable charge states are considered. The effects considered may partly account for recent experimental data on high-temperature single-electronics in semiconductor and granulated systems.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 81
    ISSN: 1090-6487
    Keywords: 73.61.Ey ; 73.40.Kp ; 73.20.Dx
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The transformation of quantum size levels into virtual levels upon a change in the electric field in an AlAs/GaAs superlattice located in the i region of a p-i-n structure is studied experimentally and theoretically. It is shown that an interfacial state at the boundary between the superlattice and the p-GaAs contact layer results in a resonant increase in the probability of photoelectron tunneling from the contact into the superlattice via Wannier-Stark levels.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 82
    Electronic Resource
    Electronic Resource
    Springer
    JETP letters 70 (1999), S. 390-395 
    ISSN: 1090-6487
    Keywords: 73.20.Dx
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract It is shown that when a strong ac electric field acts on an electron in a double quantum well, the dipole moment is an almost periodic function of the dc voltage applied to the structure. An antipolarization effect — the structure is polarized in a direction opposite to the external field — appears during one half of the period.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 83
    Electronic Resource
    Electronic Resource
    Springer
    JETP letters 70 (1999), S. 410-414 
    ISSN: 1090-6487
    Keywords: 73.20.Dx ; 71.10.Ca
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The Landau quantization for the electron gas on the surface of a sphere is considered. It is shown that in the regime of strong fields the lowest energy states are those with magnetic quantum numbers m of order of Φ /Φ0, the number of magnetic flux quanta piercing the sphere. For an electron gas of low density (semiconducting situation) it leads to the formation of an electronic stripe on the equator of the sphere in high fields.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 84
    ISSN: 1090-6487
    Keywords: 73.20.Dx
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract When a voltage is applied to double quantum wells based on AlGaAs/GaAs heterostructures with contact regions (n-i-n structures), a two-dimensional (2D) electron gas appears in one of the quantum wells. Under illumination which generates electron-hole pairs, the photoexcited holes become localized in a neighboring quantum well and recombine radiatively with the 2D electrons (tunneling recombination through the barrier). The appearance, ground-state energy, and density of the degenerate 2D electron gas are determined from the structure of the Landau levels in the luminescence and luminescence excitation spectra as well as from the oscillations of the radiative recombination intensity in a magnetic field with detection directly at the Fermi level. The electron density is regulated by the voltage between the contact regions and increases with the slope of the bands. For a fixed slope of the bands the 2D-electron density has an upper limit determined by the resonance tunneling of electrons into a neighboring quantum well and subsequent direct recombination with photoexcited holes.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 85
    Electronic Resource
    Electronic Resource
    Springer
    JETP letters 65 (1997), S. 909-914 
    ISSN: 1090-6487
    Keywords: 78.20.Bh ; 73.20.Dx
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The optical orientation of electron spins in heavily doped semiconductor structures with a valence band that is split as a result of size quantization or uniaxial deformation is investigated theoretically. It is shown that lowering the Fermi level by doping and by lowering the temperature should lead to sharp changes in the photon-energy-dependence of the average spin of the excited electrons in structures excited by circularly polarized light. This effect is due to an interchange of the dominant contribution of transitions from a light-hole subband and transitions from the heavy-hole subband in absorption.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 86
    Electronic Resource
    Electronic Resource
    Springer
    JETP letters 65 (1997), S. 215-216 
    ISSN: 1090-6487
    Keywords: 73.20.Dx
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Quantum dots based on materials with long-lived terahertz vibrations are studied. It is shown that squeezed states of such vibrations can result in microwave-frequency modulation of the optical radiation absorbed at electronic transitions in quantum dots.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 87
    ISSN: 1090-6487
    Keywords: 73.61.Ey ; 73.20.Dx ; 07.79.Fc ; 61.16.Ch
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We study InP quantum dots which are prepared by strain induced self-assembly on GaAs substrates with a GaInP buffer layer using a near field scanning optical microscope operating at near liquid He bath temperatures in the collection mode. Single quantum dots are identified spatially and spectrally due to their photoluminescence spectrum. Series of luminescence lines due to single dots of different sizes are discussed in terms of dot height and width fluctuations.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 88
    ISSN: 1090-6487
    Keywords: 73.20.Dx ; 71.35.Cc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Screening of excitonic states by a system of 2D electrons (or holes) in GaAs/AlGaAs single quantum wells is studied. With increasing concentration of 2D charge carriers, a threshold-type disappearance of excitonic states is observed in both luminescence and reflectance spectra. The higher the quality of the 2D system, the lower the corresponding threshold concentration. In the best systems, the collapse of excitonic states occurs at unexpectedly low electron densities n e =5×109 cm−2, which correspond to the mean dimensionless distance between the particles r s =8. This value far exceeds the threshold values observed for 3D systems (r s ≈2), as well as the values obtained for quantum wells in previous studies. The problem of measuring the concentration of low-density 2D charge carriers in photoexcitation conditions is solved by applying the method of optical detection of the dimensional magnetoplasma resonance. This method provides reliable measurements of the density of a 2D system to the values about 109 cm−2.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 89
    Electronic Resource
    Electronic Resource
    Springer
    JETP letters 66 (1997), S. 298-303 
    ISSN: 1090-6487
    Keywords: 73.20.Dx
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The possibility of performing single-electron computing without dissipation in an array of tunnel-coupled quantum dots is studied theoretically, taking the spin gate NOT (inverter) as an example. It is shown that the logical operation can be implemented at the stage of unitary evolution of the electron subsystem, although complete switching of the inverter cannot be achieved in a reasonable time at realistic values of model parameters. The optimal input magnetic field is found as a function of the interdot tunneling energy and intradot Coulomb repulsion energy.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 90
    ISSN: 1090-6487
    Keywords: 73.20.Dx ; 73.20.Mf ; 78.60.−b ; 78.55.Cr
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The radiative recombination spectra of two-dimensional electrons with free photoexcited holes are investigated for a wide variety of GaAs/ AlGaAs quantum wells, with different thicknesses and electron densities. It is found that for certain, close to integral, filling factors an intense line corresponding to an Auger process — radiative recombination with the emission of an additional magnetoplasmon — appears in the luminescence spectrum. The new line is shifted to lower energies with respect to the zero Landau level, and the magnetic field dependence of the energy splitting between these lines agrees with the theoretical concepts of the dispersion of magnetoplasmon excitations. This makes it possible to estimate the magnetoplasmon energy at the roton minimum.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 91
    ISSN: 1090-6487
    Keywords: 78.66.Fd ; 73.20.Dx
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Terahertz emission accompanying heating of two-dimensional electrons by a strong electric field applied along size-quantized GaAs/AlGaAs layers is observed and investigated. The emission is due to indirect optical transitions of hot electrons in the bottom size-quantization band. The experimentally obtained emission spectra are compared with the spectra calculated taking into account scattering of electrons by optical phonons, impurities, and interfacial roughness and electron-electron scattering. Satisfactory agreement is obtained. The temperature of the hot electrons is determined from a comparison of the spectra.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 92
    ISSN: 1090-6487
    Keywords: 73.20.Dx ; 42.50.Gy ; 33.80.Be
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A mechanism is proposed for obtaining intraband population inversion of electrons in size-quantization levels through the injection of electron-hole pairs into the i region of a heterostructure with quantum wells or quantum dots. Key elements of the mechanism are the simultaneous generation of interband (hv≈E g ) near-IR radiation and the presence of a “metastable” level. In quantum wells such a level can be produced by making use of the weak overlap of the wave functions of electrons in the levels of a quantum well of complicated configuration and exploiting the characteristic features of the interaction of electrons with optical phonons in polar semiconductors. In quantum dots such a level forms as a result of the phonon bottleneck effect. Estimates are made of the gain for mid-IR radiation in intraband optical transitions of electrons.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 93
    ISSN: 1090-6487
    Keywords: 73.61.Ph ; 73.50.−h ; 73.20.Dx
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Light-induced conformational transformations of the naphthacenequinone (NQ) molecules are observed by scanning tunneling microscopy (STM). NQ molecules packed in a Langmuir-Blodgett (LB) film are shown to form stable ordered structures on a surface of highly oriented pyrolytic graphite (HOPG). The local density of electronic states is found to exhibit the distinct peak which is characteristic of two-dimensional conductivity. An additional subband of empty electronic states is found for NQ molecules in form A but not in form B. The constant-height STM images of individual molecules in form A demonstrate an additional structure that is indicative of a conformational transition of the NQ molecules. This transition involves the transfer of the phenoxy group from one oxygen to another.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 94
    Electronic Resource
    Electronic Resource
    Springer
    JETP letters 64 (1996), S. 231-236 
    ISSN: 1090-6487
    Keywords: 73.20.Dx ; 84.30.Bv ; 85.30.Vw
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A new approach to the implementation of certain logical functions in quantum-dot gates for single-electron computing is proposed. It is shown that placing a gate in a uniform external magnetic field allows one to construct gates with 1) symmetric physical truth tables and 2) large (in some cases close to saturated) absolute magnitude of the average spin at the output dots. Thus two serious obstacles are removed which otherwise could present a problem in the fabrication of a set of coupled quantum-dot gates.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 95
    Electronic Resource
    Electronic Resource
    Springer
    JETP letters 68 (1998), S. 732-737 
    ISSN: 1090-6487
    Keywords: 73.20.Dx ; 73.40.Hm ; 75.70.Cn
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Self-induced filamentation of the current near the edges of a sample in the Hall geometry has been observed in the quantum-Hall-effect regime in a two-dimensional electronic system arising near a GaAs/AlGaAs heterojunction. If in the case of integer values of the filling factor ν averaged over the sample the currents flowing along opposite edges are approximately the same, then away from such a value within the quantum plateau the current is increasingly concentrated near that edge of the sample where the local value of ν is closer to being an integer. When the direction of the magnetic field or of the current changes, the filament switches to the opposite edge of the sample.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 96
    ISSN: 1090-6487
    Keywords: 73.20.Mf ; 73.20.Dx ; 85.30.Mn
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The effect of absorption of nonequilibrium acoustical phonons on the intensity of recombination of a two-dimensional electron gas in a magnetic field is investigated. The nonequilibrium acoustical phonons are emitted in the relaxation of electrons in a tunnel junction deposited on the back side of a sample with a two-dimensional electronic channel. It is demonstrated that the optical signal showing the intensity of the recombination of nonequilibrium electrons from a photoexcited size-quantization subband can serve as a sensitive detector of acoustical phonons. Because the general heating of two-dimensional carriers and the intersubband transitions stimulated by the absorption of nonequilibrium acoustical phonons lead to effects of different sign, the useful signal can be discriminated unambiguously.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 97
    ISSN: 1090-6487
    Keywords: 73.20.Dx ; 68.65.+g ; 71.35.−y
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The change in the properties of excitonic states near anticrossing is investigated experimentally. It is shown that the phase relaxation time of light excitons in a GaAs/AlGaAs symmetric double quantum well increases by a factor of five as a result of mixing of the energy states of light and heavy excitons.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 98
    ISSN: 1090-6487
    Keywords: 73.20.Dx ; 71.20.Gj ; 61.44.Br
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The nature of two-dimensional incommensurate superlattices Ll2 (MM) obtained in the precious-metals alloys Au3 Cu and Cu3 Pd is investigated on the basis of first-principles calculations of the electronic structure. It is shown that their stability can be explained by the opening of energy gaps on coinciding sections of the Fermi surface in two mutually perpendicular directions. It is important that this explanation holds only if the superlattice is treated as a superstructure with respect to ordinary superstructures (Ll2): the electronic spectrum of the superstructure and not the disordered alloy (as in the existing electronic theory of one-dimensional long-period structures) should serve as the starting spectrum. Arguments supporting the fact that in a number of quasicrystal-line substances the Ll2 (MM) phases fall between incommensurate systems and quasicrystals are presented.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 99
    Electronic Resource
    Electronic Resource
    Springer
    JETP letters 71 (2000), S. 422-425 
    ISSN: 1090-6487
    Keywords: 73.20.Dx ; 73.40.Hm ; 71.45.Lr
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A new class of collective states, which are assumed to be due to the spontaneous formation of a charge density wave (“striped” phase) upon filling high Landau levels, was recently observed in a 2D electron system based on GaAs/AlGaAs(001). The following unsolved problem is considered in the work: what is the reason for stripe pinning along the crystallographic direction [110]? It is shown that the effective mass of 2D electrons is anisotropic for a single heterojunction (001) A 3 B 5. This natural anisotropy is due to the C 2v symmetry of the heterointerface and, even being weak (0.1%), can govern the stripe direction. A magnetic field parallel to the interface induces “magnetic” anisotropy of effective mass. The competition of these two types of anisotropy (natural and magnetic) provides a quantitative description of the experiment.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 100
    Electronic Resource
    Electronic Resource
    Springer
    JETP letters 71 (2000), S. 191-194 
    ISSN: 1090-6487
    Keywords: 73.20.Dx ; 73.50.−h; 73.61.−r
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We studied a biased superlattice and revealed a considerable current response to irradiation by non-equilibrium acoustic phonons with an effective temperature on the order of a few Kelvins. We discuss two phonon source-superlattice configurations, for which the current response is caused by either interwell or intrawell electron transitions. We have shown that the response is sensitive to both direction and spectral distribution of phonons. The results explain recent experiments on the phonon-induced current response and prove that the superlattices can be used for the characterization of a high-frequency phonon flux.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...