Photoluminescence spectroscopy of metamorphic InAsSb on GaAs and Si

Abstract

Improving the production cost and yield in next-generation infrared focal plane arrays have drawn attention towards the growth of absorbing material on large-area low-cost substrates while maintaining high material quality. In this paper, we study the structural and optical properties of InAsSb bulk layers grown on lattice-mismatched semi-insulating GaAs and Ge-on-Si (Ge/Si) substrates using molecular beam epitaxy. We used X-ray diffraction (XRD) and temperature-dependent photoluminescence (PL) spectroscopy to determine the overall quality of these samples w. r.t the grown sample on the lattice-matched GaSb substrate. Analysis of the PL spectra's line shape reveals the ground state bandgap energy along with various optical transitions in each sample in the temperature range of 12 K–280 K. Furthermore, the temperature dependence of PL peak energy was analyzed, and the Integrated PL (IPL) intensity as a function of inverse temperature was used to compare the PL efficiency in each sample. The results indicate that PL is less dependent on the lattice mismatch-induced dislocations while it is mainly affected by the cracks originated from the difference in the thermal expansion coefficient of the Si substrate and the epilayer. The combination of optical and imaging analysis presented in this paper provides a deeper insight into each sample's material quality and predicts a promising path toward the application of alternative substrates in FPA imageries.