الفهرس 
Introduction and backgroundOnly 14 pages are availabe for public view
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Abstract
In the present work, we studied some of semiconductor alloys and their optical and electronic properties which are essential in the design and fabrication of optoelectronic devices. The energy band gap as known to be one of the most important devices parameter because it is strongly connected with the operating wavelength of the optoelectronic devices. Thus the ability to calculate the electronic band structure of the alloy semiconductors is an important prerequisite for any analysis of the phenomena occurring in these alloys as well as in the related devices. We studied in this work some of binary and ternary alloy semiconductor which are required to study a quaternary alloy. We focus our attention on the study of a quaternary alloy (GaxIn1-xAsyP1-y) semiconductor in zinc-blende structure which are bordered by the ternary alloys (GaxIn1-xAs), (GaxIn1-xP), (GaAs1-xPx) , (InAs1-xPx) which are bounded in their turn by four binary compounds (GaAs), (GaP), (InP) and (InAs). Beside these alloys we studied some of important binary and ternary alloys such as GaN, Si1-xGex and AlxGa1-xAs. The ternary and quaternary alloys have the advantage that a considerably wide range of band gaps can be obtained by changing the composition of the alloys. In our work, we studied the electronic band structure of the considered alloys and some of their optoelectronic properties as band gap energies, ionicity, polarity, refractive index, optical and static dielectric constants. Since these properties are strongly connected with the band gap energies which are affected with temperature and pressure, so we studied these properties of the considered alloys under the effect of temperature ranged from 0 K to 500 K and pressure ranged from 0 kbar to 120 kbar to probe the properties of the semiconductors. The effect of lattice matched substrates GaAs, InP and ZnSe on the electronic structure and the optoelectronic properties of GaxIn1-xAsyP1-y alloy are also studied. This study has opened up new generation of device applications. Our calculation are based on local empirical pseudo-potential method, where the form factors are treated as adjustable parameters that can be fit to experimental data to achieve the closed agreement of the calculated energy band gaps at some high symmetry points (Γ,X,L) with those measured by experimental results. Only a small number of form factors are sufficient for calculating the electronic band structure. In semiconductors with the zinc-blende structure, just six pseudo-potential form factors (3 symmetrical and 3 anti-symmetrical) are sufficient. The composition dependent pseudo-potentials are described by a periodic component VVCA(G) due to the virtual crystal approximation and another non periodic component Vdis(G) due to the compositional disorder effect. The calculations are performed by a routine based on the MATLAB language. The dimensions of the eigenvalue problem is 65x65 matrix, only 65 reciprocal lattice vectors grants a good convergence of the calculated results. Our calculated results are compared with the available experimental and published data and showed at least good agreement.