Demonstration of MOCVD-Grown Long-Wavelength Infrared InAs/GaSb Superlattice Focal Plane Array

Abstract

High-performance InAs/GaSb type-II superlattice infrared detectors and focal plane arrays (FPAs) are normally grown by molecular beam epitaxy (MBE). In this work, we demonstrate the first long-wavelength infrared InAs/GaSb superlattice FPA grown by metalorganic chemical vapor deposition (MOCVD) with clear image. High-quality superlattice material was obtained evidenced by sharp X-ray diffraction peaks and atomic flat surface. Electrical and optical measurements performed on single element detectors showed a 50% cut-off wavelength of $\sim 10.1~\mu \text{m}$ , a dark current density of $2.5\times 10^{-5}$ A/cm2, a peak responsivity of 0.88 A/W and a peak detectivity of $1.7\times 10^{11}$ cm $\cdot $ Hz1/2/W at 80 K. A $320\times256$ FPA with $30~\mu \text{m}$ pixel pitch was then fabricated. With an integration time of 1.9 ms and an applied bias of -0.1 V, the FPA shows an average operability of 96.96%, a non-uniformity of 4.97%, a noise equivalent temperature difference of 51.1 mK and a peak detectivity of $2.3\times 10^{10}$ cm $\cdot $ Hz1/2/W at 80 K without thinning down the substrate.