Optical properties of amorphous III–V compound semiconductors from first principles study

The optical properties of amorphous group III–V compound semiconductors were investigated through the first principles calculations. The imaginary parts ( ε 2 ) of dielectric function for amorphous GaAs, InAs, and InSb are given, respectively. There is a single broad peak found in the ε 2 spectrum. By comparing with the available experimental data of a-GaAs, it is found that the maximum of the ε 2 spectrum is sensitive to the topological local structures of amorphous materials. By comparison of the ε 2 spectrum for amorphous sample to that of the crystal, the dependence of the E1 and E2 peaks of the crystal on the local structures of amorphous sample becomes evident. The calculated results are in agreement with the available experimental data. The corresponding results should be generalized to cover the amorphous group III–V semiconductors.