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

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/cm
²
, a peak responsivity of 0.88 A/W and a peak detectivity of
$1.7\times 10^{11}$
cm
$\cdot $
Hz
^1/2
/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 $
Hz
^1/2
/W at 80 K without thinning down the substrate.