Photoluminescence of an InSb layer on a germanium substrate

Abstract

InSb layers on germanium (Ge) substrates were studied and compared with those on GaAs substrates. InSb layers were grown via molecular beam epitaxy, and their crystalline and photoluminescence (PL) properties were investigated. As the growth of InSb on Ge represents the growth of a polar semiconductor on a nonpolar semiconductor, the polarity of InSb was controlled through the soaking of the group-V element and/or migration-enhanced epitaxy at the initial growth stage and using a misoriented substrate. The insertion of a GaAs buffer layer between InSb and Ge was found to considerably improve the surface quality of the InSb layer. X-ray diffraction measurements revealed that the InSb layer grown on the misoriented substrate exhibited a better crystalline quality when it was tilted. However, one exception was observed. The origin of the tilt was discussed. By analyzing the PL emissions from the InSb layers, it was found that the intensities of the InSb peaks were strongly related to the crystalline quality. The PL emission from an InSb layer grown on Ge was successfully observed for the first time. However, the PL emission from the InSb layer grown on Ge was slightly weaker than that from InSb layers grown on GaAs substrates.