High performance Zn-diffused planar mid-wavelength infrared type-II InAs/InAs1-xSbx superlattice photodetector by MOCVD

Abstract

We report a Zn-diffused planar mid-wavelength infrared photodetector based on type-II InAs/InAs1-xSbx superlattices. Both the superlattice growth and Zn diffusion were performed in a metal-organic chemical vapor deposition system. At 77 K, the photodetector exhibits a peak responsivity of 0.70 A/W at 3.65 μm, corresponding to a quantum efficiency of 24% at zero bias without anti-reflection coating, with a 50% cutoff wavelength of 4.28 μm. With an R0A value of 3.2 × 105 ω cm2 and a dark current density of 9.6 × 10-8 A/cm2 under an applied bias of-20 mV at 77 K, the photodetector exhibits a specific detectivity of 2.9 × 1012 cm Hz1/2/W. At 150 K, the photodetector exhibits a dark current density of 9.1 × 10-6 A/cm2 and a quantum efficiency of 25%, resulting in a detectivity of 3.4 × 1011 cm Hz1/2/W.