Blueshift of bandgap energy and reduction of non-radiative defect density due to precise control of InAs-on-GaSb interface in type-II InAs/GaSb superlattice

Abstract

We have investigated the influence of As-soak parameters at InAs-on-GaSb interfaces on the structural and optical parameters of InAs/GaSb superlattices(SLs). The lattice-matched SLs were obtained for two sets of technological parameters. For a long As-soak time of 12.0 s and high V/III ratio of 10, the photoluminescence(PL) analysis indicates the presence of a non-radiative recombination channel. For a shorter time of 2.8 s and a reduced V/III ratio of 5.6, the PL excitation power dependence is close to that relevant for a clear excitonic recombination. The spectral blueshift of the bandgap energy of 23 meV was observed for SLs with GaAs-like interface thicknesses of 0.4 ML and 1.0 ML and other fixed parameters.