Temperature dependent growth of InAs/InAsSb superlattices by molecular beam epitaxy for HOT mid-wavelength infrared detectors

Abstract

High-quality InAs/InAs1-xSbx type-II superlattices (T2SLs) were grown on GaSb substrates by molecular beam epitaxy for high operating temperature (HOT) mid-wave infrared detectors. The optimal growth conditions for T2SLs were obtained by determining the temperature dependence of defects formation and the effect of V/III fluxes ratio on strain and composition. The material properties of proposed T2SLs grown with various temperature and Sb/In flux ratios were investigated using standard characterization methods, including high-resolution X-ray diffraction, atomic force microscopy, and photoluminescence (PL). The zero-order peak full width at half maximum (FWHM) of 18.4 arcsec, surface roughness less than 3 Å, strain balance, and distinct PL intensity is achieved in InAs/InAs0.65Sb0.35 T2SL. Temperature-dependent PL, ranging from 70 K to 240 K, shows a slight peak shift from 4.74 μm to 5.14 μm. The temperature-sensitive parameter α extracted from Varshni fitting is smaller than those of InAs/GaSb and bulk InAsSb, indicating the promising perspective of InAs/InAs1-xSbx T2SLs for HOT mid-wave infrared photodetectors.