Original scientific paper
Structural, elastic, electronic and lattice dynamic properties of GaPxAsySb1−x−y alloys lattice matched to different substrates
B. Ghebouli
; Laboratory for Studying Surfaces and Interfaces of Solid Maretials, University Ferhat Abbas, Sétif 19000, Algeria
M. A. Ghebouli
; Departement of Physics, University Center, Bordj-Bou-Arréridj 34000, Algeria
M. Fatmi
; Research Unit on Emerging Materials, University Ferhat Abbas, Sétif 19000, Algeria
Abstract
Information on the energy band gaps, the lattice parameter and the lattice matching to available substrates is a prerequisite for many practical applications. A pseudopotential plane-wave method, as implemented in the ABINIT code, is used to the GaPxAsySb1−x−y quaternary alloy lattice matched to GaAs and InP substrates to predict their energy band gaps, elastic constants and lattice dynamic properties. The ranges of compositions for which the alloy is lattice-matched to GaAs and InP are determined. A very good agreement is obtained between the calculated values and the available experimental data of GaAs and GaAs0.5Sb0.5 parents. The compositional dependence of direct and indirect band gaps has been investigated. Note that a phase transition occurred at As composition of 0.018 and 0.576 for GaPxAsySb1−x−y within InP and GaAs substrates. The static and high-frequency dielectric constants and refractive index are indeed inversely proportional (proportional) to the fundamental band gap for GaPxAsySb1−x−y within InP (GaAs) substrates. We study the variation of elastic constants, the optical phonon frequencies (ωTO and ωLO) and the Born effective charge Z* with As concentration.
Keywords
structural properties; electronic properties; first principles calculations; lattice dynamic properties; Born effective charge; elastic properties
Hrčak ID:
302804
URI
Publication date:
1.9.2010.
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