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  • 1
    Electronic Resource
    Electronic Resource
    Synthesis, structure and properties of the polychalcogenides [M"4Te"1"2]^4^- (M=Cd, Hg)
    Amsterdam : Elsevier
    Inorganica Chimica Acta 224 (1994), S. 163-169 
    Details
    ISSN: 0020-1693
    Keywords: Crystal structures ; Polychalcogenide complexes ; Tellurium complexes
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0020-1693(94)01014-5
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  • 2
    Electronic Resource
    Electronic Resource
    Dielectric response functions of heavily doped zincblende semiconductors with finite particle lifetime (1992)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 72 (1992), S. 4139-4147 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The dielectric response functions in the valence bands and in the conduction band of heavily doped zincblende semiconductors have been evaluated using the self-consistent field method and incorporating the finite lifetime of particles in the relaxation time approximation. Scattering rates of injected electrons are calculated with the Born approximation in the dielectric response function formalism at finite temperature. The finite particle lifetime introduces significant modifications to the spectral density function {Im[−1/ε(q,ω)]} at small q, where collective excitations (i.e., coupled phonon-plasmon modes) are heavily damped due to collisions. However, these modifications are small at large q. At the same time, the scattering rates of injected electrons are strongly affected by the temperature dependence of these effects, which are particularly significant for p-type semiconductors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.352222
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  • 3
    Electronic Resource
    Electronic Resource
    Effects of interface phonon scattering in multiheterointerface structures (1992)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 72 (1992), S. 2282-2287 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: In this paper, the commonly used but idealistic formulation of quantized optical-phonon modes for a heterostructure system with only two heterojunctions (i.e., single quantum-well structures) is extended to the more realistic case of multiheterointerface structures. By applying the macroscopic dielectric continuum approach, dispersion relations and interaction Hamiltonians for interface-phonon modes are derived for a double-barrier structure and scattering rates based on these results are used to determine the range of practical validity of the idealistic model using interaction Hamiltonians appropriate for single quantum wells with infinite barrier widths. It is found that when the dimensions of the structures are larger than approximately 30 A(ring), this simplified description can be applied to multiheterointerface structures in general with reasonable accuracy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.351569
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  • 4
    Electronic Resource
    Electronic Resource
    Theoretical calculation of longitudinal-optical-phonon lifetime in GaAs (1994)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 76 (1994), S. 3905-3907 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The anharmonic decay of longitudinal-optical (LO) phonons in zinc-blende semiconductors has been studied. Based on an approach in which the anharmonic crystal potential is estimated using the theory of elasticity, the lifetime of LO phonons via emission of two acoustic phonons is calculated as a function of lattice temperature and phonon wave vector. Application of this model to bulk GaAs shows an excellent agreement with available experimental data. Since the parameters employed in the model can be obtained experimentally, the approach provides a useful tool to investigate LO-phonon lifetimes in semiconductors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.358498
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  • 5
    Electronic Resource
    Electronic Resource
    Reduction of interface phonon modes using metal-semiconductor heterostructures (1993)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 73 (1993), S. 2338-2342 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Based on a simplified analysis of perfectly conducting metals, it has been suggested qualitatively that establishing metal-semiconductor interfaces at the heterojunctions of polar semiconductor quantum wells introduces a set of boundary conditions that dramatically reduces or eliminates unwanted carrier energy loss caused by interactions with interface longitudinal-optical (LO) phonon modes. In this article, it is theoretically demonstrated that comparable reductions in LO phonon scattering strengths may be achieved for metal-semiconductor structures with metal having realistic conductivities and Thomas–Fermi screening lengths.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.353139
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  • 6
    Electronic Resource
    Electronic Resource
    Optical properties of ultrathin GaAs/AlAs quantum well structures with an electric field (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 8675-8681 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A theoretical study of the optical properties of GaAs/AlAs quantum well structures in the presence of an electric field is presented. In the first part of the article, interband transitions from the valence band to the conduction band are studied near the type-I to type-II transition point. In the second part, the effect of the electric field on intersubband transitions within the conduction band is considered. The band structure is calculated using a second-nearest-neighbor empirical sp3 tight binding method including spin–orbit effects. Interband and intersubband transition energies, optical matrix elements, and absorption coefficients are given as functions of the electric field. It is shown that the optical properties of these structures can be modified significantly with field near the anticrossing point. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.362493
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  • 7
    Electronic Resource
    Electronic Resource
    Quantized acoustic phonon modes in quantum wires and quantum dots (1994)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 76 (1994), S. 4670-4675 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Acoustic phonon modes in isotropic cubic media are derived for a number of quantum-wire and quantum-dot geometries of significant interest in nanoelectronics and optoelectronics. In each case, the mode amplitude is determined by requiring that the mode energy be given by that of the properly quantized phonon. For the case of cylindrical quantum wires and quantum dots with rectangular faces, the Hamiltonians for the deformation potential interactions are derived. These quantized acoustic modes and the associated deformation potential Hamiltonians provide a basis for modeling carrier-acoustic-phonon interactions in a variety of mesoscopic devices. Our new results supplement previous treatments of related piezoelectric effects in cylindrical quantum wires.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.357305
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  • 8
    Electronic Resource
    Electronic Resource
    Strain effects on optical gain in wurtzite GaN (1997)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 82 (1997), S. 386-391 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Strain effects on optical gain in hexagonal bulk GaN are calculated and explained in terms of the change in the effective hexagonal crystal field component. Qualitatively, even unstrained wurtzite structures correspond to cubic crystals with a proper biaxial stress applied. Such biaxial stress results in effective tensile deformation along the c axis ([111] direction in cubic crystals) and compressive strain in the perpendicular plane. Therefore, the light mode with a polarization vector parallel to the c axis is suppressed, while the mode with a perpendicular polarization is enhanced in wurtzite structures. Thus, compared to cubic structures with similar material parameters, a strong optical anisotropy of wurtzites results in enhanced gain for certain light polarizations, which make wurtzite structures superior for lower-threshold lasing. These qualitative arguments are illustrated by numerical calculations of optical gain in biaxially strained wurtzite GaN, based on a 6×6 envelope-function Hamiltonian. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.365824
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  • 9
    Electronic Resource
    Electronic Resource
    Transient ballistic transport in GaN (1997)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 81 (1997), S. 2901-2903 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Monte Carlo simulations have been used to study the spatial scales of electron ballistic transport in GaN. The large optical phonon energy (92 meV) and the large intervalley energy separation between the Γ and satellite conduction band valleys (≥1.5 eV) suggest an increasing role for ballistic electron effects in GaN, especially when compared with most III–V semiconductors such as GaAs. However, the concomitant high polar optical phonon scattering rate in GaN tends to diminish the desirable electron transport properties. The relationships between these two factors have been studied for the range of electric fields up to 140 kV/cm and lattice temperatures between 300 and 600 K. We demonstrate that in most cases electrons in GaN lose their directed average velocity over distances of only 100−200 Å, and ballistic transport occurs only over such short distances. The main cause for the small spatial scales of ballistic transport in GaN is the strong electron–optical phonon coupling which results in rapid relaxation of the directed electron velocity.© 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.363952
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  • 10
    Electronic Resource
    Electronic Resource
    Anti-inflammatory effect of germanium-concentrated yeast against paw oedema is related to the inhibition of arachidonic acid release and prostaglandin E2 production in RBL 2H3 cells (2005)
    Oxford, UK : Blackwell Science Ltd
    Autonomic & autacoid pharmacology 25 (2005), S. 0 
    Details
    ISSN: 1474-8673
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Chemistry and Pharmacology , Medicine
    Notes: 1 To investigate anti-inflammatory activity of organic germanium, we measured the effect of germanium-concentrated yeast on arachidonic acid release, prostaglandin E2 (PGE2) production, histamine release, and intracellular H2O2 or hydroperoxide generation in RBL 2H3 cells, and carrageenan-induced paw oedema in rats. 2 Germanium-concentrated yeast dose-dependently inhibited carrageenan-induced paw oedema, suggesting that germanium-concentrated yeast has anti-inflammatory activity in acute inflammation. 3 Germanium-concentrated yeast significantly inhibited melittin-induced arachidonic acid release and PGE2 production in RBL 2H3 cells. 4 Germanium-concentrated yeast did not affect melittin-induced histamine release and silica-induced intracellular H2O2 or hydroperoxide generation in RBL 2H3 cells. 5 These results suggest that anti-inflammatory activity of germanium-concentrated yeast appears partly to be related to the inhibition of arachidonic acid release and PGE2 production in RBL 2H3 cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1474-8673.2005.00335.x
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