Growth and characterization of InGaAs/InAsSb superlattices by metal-organic chemical vapor deposition for mid-wavelength infrared photodetectors

Abstract InGaAs/InAsSb superlattices (SLs) were grown on InAs substrates by metal-organic chemical vapor deposition (MOCVD) for potential applications in mid-wavelength infrared photodetectors. Three In1-xGaxAs/InAs0.73Sb0.27 ternary SL samples, with x = 0.2, 0.25, and 0.3, were grown and investigated by X-ray diffraction, atomic force microscopy and photoluminescence. Excellent structural qualities were achieved with lattice mismatches of less than 0.15% and atomically smooth surfaces with a roughness of only 0.18–0.19 nm. Strong photoluminescence (PL) emissions were observed at around 3.7 μm at 77 K. Besides, Varshni fitting indicates the temperature-sensitive parameter α in the InGaAs/InAsSb SLs is only half of that in InAs/InAsSb SLs, making them suitable for high temperature operation.