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Hole Effective Mass (hole + effective_mass)

Distribution by Scientific Domains
Physics and Astronomy100%

Selected Abstracts

Hole,polar phonon interaction scattering mobility in chain structured TlSe0.75S0.25 crystals

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 7 2009
A. F. Qasrawi
Abstract In this study, the electrical resistivity, charge carriers density and Hall mobility of chain structured TlSe0.75S0.25 crystal have been measured and analyzed to establish the dominant scattering mechanism in crystal. The data analyses have shown that this crystal exhibits an extrinsic p-type conduction. The temperature-dependent dark electrical resistivity analysis reflected the existence of three energy levels located at 280 meV, 68 meV and 48 meV. The temperature dependence of carrier density was analyzed by using the single donor,single acceptor model. The carrier concentration data were best reproduced assuming the existence of an acceptor impurity level being located at 68 meV consistent with that observed from resistivity measurement. The model allowed the determination of the hole effective mass and the acceptor,donor concentration difference as 0.44m0 and 2.2 × 1012 cm,3, respectively. The Hall mobility of the TlSe0.75S0.25 crystal is found to be limited by the scattering of charged carriers over the (chain) boundaries and the scattering of hole,polar phonon interactions above and below 300 K, respectively. The value of the energy barrier height at the chain boundaries was found to be 261 meV. The polar phonon scattering mobility revealed the high-frequency and static dielectric constants of 13.6 and 15.0, respectively. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Effects of lattice-mismatch induced built-in strain on the valence band properties of wurtzite ZnO/Zn1,xMgxO quantum well heterostructures

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 1 2007
K. Zitouni
Abstract We present a theoretical study of the effects of lattice-mismatch induced built-in strain on the electronic properties of valence band states in wurtzite ZnO/Zn1,xMgxO Quantum Well (QW) heterostructures. In this purpose, a 6x6 k·p method has been used to incorporate the effects of strain and nonparabolicity. The energies corresponding to the transitions between conduction band (C), heavy hole (HH), light hole (LH) and crystal-field split-off hole (CH) bands have been calculated as a function of Mg composition and strain. We have also calculated the energy dispersions and wave functions of strained wurtzite ZnO. It is found that ZnO is always under a biaxial tensile strain, in the whole Mg composition range investigated (x < 40%). As a consequence, the light hole valence subband is shifted upwards with respect to the corresponding heavy hole valence subband, resulting in a reduction of ZnO direct band gap by almost 6% when x = 35%. This is found to result in turn in a significantly reduced in-plane hole effective mass at the top of the valence band which is always LH-like. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

The band structure of a layered Hg3TeCl4 crystal formed by energy states of HgCl2 and HgTe crystals

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 8 2008
M. Sznajder
Abstract The ab-initio calculated band structure of a not as yet investigated orthorhombic Hg3TeCl4 crystal (Pbca, D152h) was analyzed by means of the elementary energy-bands concept. It was demonstrated that this band structure originates from that of a layered HgCl2 dielectric deformed by the presence of the HgTe structural elements. Further, it was revealed that the valence band of Hg3TeCl4 is composed of the 8-branch elementary energy bands corresponding to the actual Wyckoff position c (x, y, z) of D152h group that indicates the presence of ionic and covalent contributions to the chemical bonding in the crystal. The existence of Davydov splitting in the 8-branch elementary energy band situated in the low-energy range of the valence band was observed, which is typical for layered crystals with a weak interlayer interaction between translationally nonequivalent structural units. It was shown that the anisotropy of the electron and hole effective masses does not correspond to the macroscopic anisotropy of the crystal and an explanation of this behaviour was proposed. The obtained parameters of the crystal (direct energy gap Eg = 2.49 eV as well as values of the estimated electron effective masses) indicate that it could find an application in optoelectronics. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Angular and temperature-related specific features of averaging of hole effective masses in p-Ge at low temperatures

ANNALEN DER PHYSIK, Issue 12 2009
T. Tisnek
Abstract Microwave magnetoresistance of lightly doped (nondegenerate) p-Ge has been studied by the electron spin resonance method, which can record the derivative of the microwave absorption with respect to the magnetic field. The change in the absorption is proportional to that in the conductivity of the semiconductor in the magnetic field (magnetoresistance). It was found that the averaging time of the light and heavy holes effective masses depends on temperature and on the magnetic field direction in a sample. An analysis of the derivative made it possible to determine regions of the fastest effective mass averaging. [source]