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  • 1
    Electronic Resource
    Electronic Resource
    Calculation of the wave-vector-dependent interband impact-ionization transition rate in wurtzite and zinc-blende phases of bulk GaN (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 8838-8840 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We present calculations of the wave-vector-dependent interband impact-ionization transition rate in wurtzite and zinc-blende phases of bulk GaN. The transition rate is determined by integrating Fermi's golden rule for a two-body, screened Coulomb interaction over the possible final states using a numerically generated dielectric function and pseudowavefunctions. The full details of all relevant conduction and valence bands in zinc-blende and wurtzite GaN are included from an empirical pseudopotential calculation. It is found that the transition rate is consistent with a relatively "soft'' threshold energy. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.362509
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  • 2
    Electronic Resource
    Electronic Resource
    Electronic transport studies of bulk zincblende and wurtzite phases of GaN based on an ensemble Monte Carlo calculation including a full zone band structure (1995)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 78 (1995), S. 1033-1038 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The ensemble Monte Carlo technique including the details of the first four conduction bands within the full Brillouin zone is used to calculate the basic electronic transport properties for both zincblende and wurtzite crystal phases of bulk gallium nitride. The band structure throughout the Brillouin zone is determined using the empirical pseudopotential method. Calculations of the electron steady-state drift velocity, average energy, valley occupancy and band occupancy in the range of electric fields up to 500 kV/cm are presented. It is found that the threshold electric field for intervalley transfer is greater and that the second conduction band is more readily occupied in wurtzite than in zincblende GaN over the range of electric fields examined here. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.360405
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  • 3
    Electronic Resource
    Electronic Resource
    Hole transport properties of bulk zinc-blende and wurtzite phases of GaN based on an ensemble Monte Carlo calculation including a full zone band structure (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 80 (1996), S. 4429-4436 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: In this paper, we present calculations of the hole transport properties of bulk zinc-blende and wurtzite phase GaN at field strengths at which impact ionization does not occur significantly. The calculations are made using an ensemble Monte Carlo simulator, including the full details of the band structure and a numerically determined phonon scattering rate based on an empirical pseudopotential method. Band intersection points—including band crossings and band mixings—are treated by carefully evaluating the overlap integral between the initial and possible final drift states. In this way, the hole trajectories in phase space can be accurately traced. It is found that the average hole energies are significantly lower than the corresponding electron energies for the field strengths examined. This result is most probably due to the drastic difference in curvature between the uppermost valence bands and the lowest conduction band. The relatively flat valence bands impede hole-heating, leading to low average hole energy. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.363422
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  • 4
    Electronic Resource
    Electronic Resource
    Modeling of band-to-band tunneling transitions during drift in Monte Carlo transport simulations (2000)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 88 (2000), S. 1488-1493 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The conventional method of semiconductor charge carrier transport investigations using full band ensemble Monte Carlo simulations is extended to allow for tunneling between bands during accelerated drift of the carriers. The essentially classical picture of transport, as simulated, is preserved by implementing a stochastic selection of the band index of the initial state of each scattering process associated with phonons, with impurities, or with impact ionization. Relative probabilities for the band assignment are calculated from the overlap integrals of the cell-periodic parts of Bloch wave functions belonging to different bands, for k-vectors along the carrier k-space trajectory between successive scattering events. As an example, the method is applied to Monte Carlo transport simulations for holes in 4H SiC in a homogeneous applied electric field. Tunneling between valence bands during the drift phases is shown to have a significant impact on the carrier energy distributions when large electric fields are applied, and on physical parameters that directly depend on the carrier energy, such as the hole initiated impact ionization coefficient. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.373844
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  • 5
    Electronic Resource
    Electronic Resource
    AlGaN/GaN heterojunction bipolar transistor structures-design considerations (2000)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 88 (2000), S. 1067-1072 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The potential of III-nitride materials for the fabrication of bipolar transistors is investigated theoretically. Several different AlGaN/GaN n–p–n heterojunction bipolar transistor structures are examined through calculations of their band profiles and majority carrier distributions in equilibrium and in forward active mode. Spontaneous and piezoelectric polarization charges are utilized to create large hole sheet carrier densities in the base layer, thus minimizing the base spreading resistance. At the same time, a large accelerating field in the base can help reduce the base transit time of the electrons and, hence, increase the current gains of these devices. The temperature dependence of the hole concentration in the base is also investigated. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.373778
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  • 6
    Electronic Resource
    Electronic Resource
    Self-consistent calculation of the electronic structure of semiconductor quantum wires: Semiclassical and quantum mechanical approaches (1993)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 74 (1993), S. 6234-6241 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Efficient self-consistent calculations of dynamically one-dimensional electron gas systems using the finite element method with nonuniform mesh of triangular elements have been implemented. Both self-consistent semiclassical and self-consistent quantum mechanical calculations are carried out. In the semiclassical treatment, Poisson's equation is solved self-consistently with the induced electron density determined by the Thomas–Fermi continuum formalism. Newton's method is implemented to ensure fast convergence. In the quantum mechanical treatment, quasi-one-dimensional subband levels are determined by solving the effective mass Schrödinger equation and the induced electron density is determined by filling the occupied subbands according to Fermi–Dirac statistics for zero temperature. Self-consistency is achieved using Newton's method with an approximate Jacobian derived from the Thomas–Fermi approximation. Etched ridge and split gate semiconductor quantum wires based on selectively doped AlGaAs/GaAs heterostructures are studied. The results of the semiclassical and quantum mechanical calculations are compared. We find that the two approaches predict similar lineal densities of induced electrons for a range of cases but that the dependence of electron density on external parameters can differ significantly. The resulting potential shapes and electron distributions can also be quite different. Specifically, the semiclassical approach results in shallower confining potential wells and less spread of the electron distribution in the direction perpendicular to the heterointerface than is found in the quantum mechanical approach.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.355197
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  • 7
    Electronic Resource
    Electronic Resource
    Exchange effect in coupled one-dimensional electron-gas systems (1992)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 71 (1992), S. 1318-1321 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: An exchange effect in one-dimensional quantum-wire electron-gas systems is investigated. The theoretical study presented shows that the electron population of a symmetrical structure consisting of two parallel quantum wires in close proximity may exhibit bistability with all electrons contained in one of the quantum wires. Compared to a similar effect in a two-dimensional system reported earlier, the excitation energy associated with the transfer of one electron is found to be much larger. For certain configurations, this energy can be as large as ∼50 meV. The theory predicts the exchange-induced bistability to exist in realistic configurations, and it may possibly be used in practical electronic devices such as memory elements.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.351249
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  • 8
    Electronic Resource
    Electronic Resource
    Hydrostatic-pressure dependence of the photoconductivity of single-crystal pentacene and tetracene (2001)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 79 (2001), S. 2731-2733 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Pentacene and tetracene show readily observable photoconductivity when illuminated with light in the blue part of the visible spectrum. We measured the change of photoconductivity with hydrostatic pressure in single-crystal samples of both materials. Possible mechanisms for the observed increase in photoconductivity with pressure are discussed. We conclude that a carrier-mobility increase under pressure is most likely to cause the increase in photoconductivity in the case of pentacene. For tetracene, changes in the absorption spectrum in the range of the excitation wavelengths may also be significant. We also observe a phase transition near 0.3 GPa in tetracene, in agreement with previous results. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1410878
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  • 9
    Electronic Resource
    Electronic Resource
    Exchange effect in coupled two-dimensional electron gas systems (1991)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 59 (1991), S. 2165-2167 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The distribution of electrons in two parallel two-dimensional electron sheets in close proximity at low temperatures is investigated. We find that due to the exchange interaction a symmetric structure may have a ground state in which all electrons are transferred to one of the sheets. This occurs if the separation between the two systems is sufficiently small and the two-dimensional electron gas density is sufficiently low. The exchange interaction consequently leads to a bistability with respect to electron population in the two-sheet system which may be useful for future electronic devices, such as memory elements.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.106116
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  • 10
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    Transient effects controlling the charge carrier population of organic field effect transistor channels (2010)
    American Institute of Physics
    Details
    Publication Date: 2010-05-15
    Print ISSN: 0021-8979
    Electronic ISSN: 1089-7550
    Topics: Physics
    Published by American Institute of Physics
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