Metal organic chemical vapor deposition of metaphorphic InAs–GaSb superlattices on (0 0 1) GaAs substrates for mid-IR photodetector applications

InAs/GaSb superlattices (SLs) were grown on (0 0 1) GaAs substrates by metal organic chemical vapor deposition. A thin low temperature (LT) GaSb nucleation layer followed by a 250 nm thick high temperature (HT) GaSb buffer layer were introduced before the growth of the SLs and their growth conditions were optimized. The effects of growth temperature and GaSb growth rate on the morphology and structural properties of the SL were systematically studied. Atomic force microscopy, photoluminescence, transmission electron microscopy and X-ray diffraction were used to characterize the grown structures. Generally, nanopipes, about 100 nm in diameter, were found in the grown structures and their formation depends strongly on the growth temperature and the GaSb growth rate in growing the SL. By optimizing these parameters, high-quality InAs/GaSb SLs without nanopipes and with sharp interfaces have been realized.