ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Steady holographic gratings in semiconductor multiple quantum wells (1992)
    Springer
    Applied physics 55 (1992), S. 25-29 
    Details
    ISSN: 1432-0630
    Keywords: 42.40 ; 78.65
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract A theoretical model based on the Dember mechanism is proposed to describe the steady state photorefractive gratings generated in semiconductor multiple quantum wells (MQW). It has been applied to an GaAs/AlGaAs MQW in parallel configuration (external electric field applied parallel to the MQW layers) for which recent experimental data are available. The model predicts a dependence of the first-order diffraction efficiency on the applied field in qualitative accordance with experiments, including the occurrence of saturation at high field values. Absolute values of the efficiencies are in good agreement with the experimental ones. Finally, high second-order diffraction efficiencies, associated with the development of a perpendicular space charge field, are also predicted by the model.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00324597
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Effect of Bias Voltage on the Physical Properties of Hydrogenated Amorphous Carbon Films Grown by Electron Cyclotron Resonance Chemical Vapour Deposition (2006)
    s.l. ; Stafa-Zurich, Switzerland
    Advances in science and technology Vol. 48 (Oct. 2006), p. 17-23 
    Details
    ISSN: 1662-0356
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Natural Sciences in General , Technology
    Notes: In the present work, a-C:H films have been grown from argon/methane gas mixtures byElectron Cyclotron Resonance Chemical Vapour Deposition (ECRCVD). The effect of theapplication of a dc bias voltage to the silicon substrate material on the structural,morphological and mechanical properties of the films has been explored by multiple analysistechniques such as IR and micro-Raman spectroscopy, AFM, nano-indentation and pin-ondiskwear testing. In general, within the range of –300 V to +100 V applied substrate bias wehave observed a strong correlation between all measured properties of the grown a-C:H filmsand the ion energy. Though it is known that the ion energy is one of the crucial parameters inplasma grown films, this work clearly shows that the properties of the a-C:H layers can differgreatly and indicates a threshold energy for the production of hard, low-friction coatings inthe order of 80-90 eV. Moreover, this threshold energy is also combined with a sharptransition from rough, cauliflower-like film surfaces towards ultrasmooth, featurelesstopographies. This correlation suggests that at energies higher than 80 eV the ionbombardment affects simultaneously the surface morphology and the internal bondingstructure
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/42/transtech_doi~10.4028%252Fwww.scientific.net%252FAST.48.17.pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Localization in highly strained In"0"."3"5Ga"0"."6"5As/GaAs ultrathin quantum wells
    Amsterdam : Elsevier
    Superlattices and Microstructures 14 (1993), S. 39 
    Details
    ISSN: 0749-6036
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1006/spmi.1993.1100
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Wannier–Stark localization in asymmetric double-well superlattices (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 8106-8108 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The Wannier–Stark localization of miniband states has been investigated in an asymmetric double-well superlattice. The period consists of 3.4 and 2.0 nm GaAs quantum wells separated by 1.4 nm Al0.15Ga0.85As barriers. Photocurrent spectra at 6 K reveal that the lowest excitonic peak near flat band splits up into eight peaks at moderate electric fields. At very high fields only one peak remains. The observed transitions are attributed to the Stark ladder splitting of the wide-well miniband only. This type of superlattice introduces a new degree of freedom for the tailoring of electro-optic devices. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.362367
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Effect of thermal annealing on Te precipitates in CdTe wafers studied by Raman scattering and cathodoluminescence (1995)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 77 (1995), S. 2806-2808 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A combination of Raman scattering and cathodoluminescence techniques has been used to study the spatial distribution of Te precipitates in the volume of CdTe wafers. Starting with the as-grown crystals with random distribution of precipitates over the whole volume, improvement at different stages of thermal annealing is demonstrated. As-grown p-CdTe wafers were annealed at 500–600 °C either in Ga melt or in Cd vapor for 2 or 22 h. The kinetics of dissolution of Te precipitates was found to be similar for both the Ga melt and Cd vapor annealing processes. Short-time annealing causes the disappearance of small Te precipitates, while the larger ones, 5–10 μm in size which decorate the extended structural defects, still remain. After a long-time annealing, the complete disappearance of Te precipitates occurs in the wafers volume. Interestingly, it was observed that the disappearance of Te precipitates during annealing starts in the central part of the bulk wafer and is followed by a precipitate gettering at the wafer surface. This implies that it is possible to obtain precipitate-free CdTe wafers by postgrowth annealing. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.358687
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Electronic energy levels of quantum-well wires (1993)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 73 (1993), S. 5027-5031 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: An efficient variational method to solve the two-dimensional Schrödinger equation using a basis set of cubic B splines is introduced. The method, which uses the effective mass theory and the envelope function approximation, is applied to find the energy levels of quantum-well wires of different shapes. Finally, for rectangular wires a very simple method based on a special decomposition of the V(x,y) potential is used to reduce the problem to two one-dimensional equations. This gives very good results even for very narrow wires, where the conventional decomposition V(x,y)=V(x)+V(y) fails.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.353772
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Depth-resolved microspectroscopy of porous silicon multilayers (1999)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 75 (1999), S. 977-979 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have measured depth-resolved microphotoluminescence (PL) and micro-Raman spectra on the cross section of porous silicon multilayers to sample different layer depths. The PL emission band gets stronger, blueshifts, and narrows at the high porosity layers. On the contrary, the Raman band weakens and broadens. This band is fitted to the phonon confinement model. With the bulk silicon phonon frequency and its linewidth as free parameters, we obtain crystallite size, temperature, and stress as a function of depth. Sizes are larger than those estimated from PL. Laser power was reduced to eliminate heating effects. Compressive stresses in excess of 10 kbar are found in the deepest layer due to the lattice mismatch with the substrate. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.124572
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Influence of wavelength on the Raman line shape in porous silicon (1998)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 84 (1998), S. 2349-2351 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The line shape of the one phonon Raman peak has been used extensively in the literature to estimate the crystallite size in porous silicon. However it has been shown that the line shape obtained on top surface experiments depends on the excitation wavelength. Because the porosity depends on depth, previous results are masked by the change in penetration depth. In this communication we report depth-resolved micro-Raman spectra at 514.5 and 632.8 nm. The spectra were measured at different points along a cross section of porous silicon films. We show that even when the same layer and, therefore, the same porosity is probed the Raman peak is broader at shorter wavelengths. To explain the results we suggest a contribution of indirect gaps to the resonant Raman cross section induced by quantum confinement. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.368303
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Temperature dependence of the electronic coherence of GaAs-GaAlAs superlattices (1990)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 56 (1990), S. 2545-2547 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have shown that the coherence length of electrons in a 55-A(ring)-period GaAs-GaAlAs superlattice does not depend strongly on temperature in the range 5–292 K, varying from 17 periods at 5 K to a minimum of nine periods at room temperature. The quantum coherence was determined by photocurrent spectroscopy experiments that exploit the formation of Stark ladders in superlattices under electric fields.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.102882
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Observation of miniband formation in the CdTe/Cd1−xMnxTe quantum well system (1990)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 57 (1990), S. 1769-1771 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report the effects of perpendicular electric fields on the eigenenergies of the CdTe/Cd1−xMnxTe quantum well system. The samples are probed at 6 K using photoluminescence. In an electric field, the photoluminescence spectra of wide-barrier quantum well samples red shifted, consistent with the quantum-confined Stark effect. The spectra of narrow-barrier superlattice samples blue shifted, indicative of miniband reduction to localized states. A linear blue shift was observed up to a field of 50 kV/cm after which saturation occurred. Additionally, we have observed luminescence which appeared to arise from transitions between adjacent wells. No striking effects were observed at the paramagnetic-spin glass transition temperature.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.104062
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...