<title>InAs/GaSb superlattices characterized by high-resolution x-ray diffraction and infrared optical spectroscopy</title>

Abstract

We have studied InAs/GaSb superlattices (SLs) grown with either InSb-like or GaAs-like interfaces (IFs) on top of a GaSb buffer layer on (100) GaAs substrates. The InAs layer thickness was varied from 4 to 22 monolayers (ML) while the GaSb layer thickness was kept fixed at 10 ML. Two-dimensional high-resolution x-ray diffraction space maps using symmetric and asymmetric reflections, allowed us to determine independently the lattice constants parallel and perpendicular to the growth direction. The GaSb buffer layer was found to be fully relaxed whereas the SLs with InSb-like IFs were found to be coherently strained to the lattice parameter of the buffer layer for InAs layer thicknesses exceeding 6 ML. For SLs with GaAs-like IFs a comparison of measured with simulated x-ray reflection profiles enabled us to deduce the strain distribution within the SL stack, which showed increasing strain relaxation with increasing distance from the buffer layer. The dependence of the effective band gap on the SL design assessed by photoluminescence and photocurrent spectroscopy, is compared with theoretical calculations.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.