Molecular Beam Epitaxy Growth and Optical Characterization of Al[sub x]In[sub 1-x]Sb∕GaAs Heterostructures

Abstract

Optical properties of AlxIn1‐xSb semiconductor alloys with x varied in the range x = 0–0.52 were explored. The alloy layers were grown by molecular beam epitaxy on highly lattice‐mismatched GaAs substrates, mediated by thick AlSb buffer layers and strained Insb/AlxIn1‐xSb superlattices to reduce the extended defect density. Fourier‐transform infrared spectroscopy was employed to characterize the alloys. Taking into account the conduction band non‐parabolicity, the energy gap values (Eg) of the alloys were determined from the fundamental absorption edge. This enabled one to refine the bowing parameter of the Eg(x) dependence for AlxIn1‐xSb alloys. It has been found to be of 0.32 eV, i.e. by 0.11 eV less than the generally referred value.