Fundamental absorption edge of semiconductor alloys with the direct-gap energy-band structure

A procedure convenient for practical application to the calculations of the fundamental absorption spectra of semiconductor alloys with the direct-gap energy-band structure is developed. The procedure is based on the knowledge of the fundamental absorption spectra of binary constituents of the alloy, takes into account the nonparabolic structure of the conduction band, and involves only one adjustable parameter that characterizes the inhomogeneous broadening of the spectra. The procedure is tested by the examples of the best-studied and practically most important Al (x) Ga1 - x As alloys, the (Al (x) Ga1 - x )(0.5)In0.5P alloys isostructural to GaAs, and the Ga (x) In1 - x As alloys isostructural to InP. The procedure can be used in the case of other III-V and II-VI compounds. The results make it possible to calculate the intrinsic luminescence spectra of the alloys.