Material parameters of In1−<i>x</i>Ga<i>x</i>As<i>y</i>P1−<i>y</i> and related binaries

Various models for calculation of physical parameters in compound alloys are discussed and the results for In1−x Gax Asy P1−y quaternaries are presented. The model used is based on a linear interpolation scheme, and therefore necessitates known values of the parameters for the related binary and ternary alloys. The material parameters considered in the present study can be classified into the following eleven groups: (1) lattice constant and crystal density, (2) thermal expansion coefficient, (3) electronic-band structure, (4) external perturbation effect on the lowest-direct gap, (5) effective mass, (6) dielectric constant, (7) Fröhlich coupling parameter, (8) elastic properties, (9) piezoelectric properties, (10) deformation potential, and (11) excitonic effect. Of particular interest is the deviation of material parameters from linearity with respect to the alloy composition. It is found that the present model provides generally acceptable parameters, in good agreement with the existing experimental data. A detailed discussion is also given on the acceptability of such interpolated parameters from an aspect of the solid-state physics. Key properties of the material parameters for a variety of In1−x Gax Asy P1−y device applications are also discussed.