Demonstration and Performance Assessment of Large Format InP–InGaAsP Quantum-Well Infrared Photodetector Focal Plane Array

摘要

There have been various studies showing that InP–InGaAs quantum-well infrared photodetectors (QWIPs) are potential alternatives to AlGaAs–GaAs QWIPs in the long wavelength infrared (LWIR) band, especially for applications requiring high responsivity. Being on InP substrate, this material system also offers lattice matched mid-wavelength infrared (MWIR)/LWIR dual band QWIP stack when it is used with the AlInAs–InGaAs system. It is desirable to extend the cut-off wavelength of InP based LWIR QWIPs to $sim {hbox {9}} mu{hbox {m}}$, which can be accomplished by replacing the QW material with InGaAsP. In this paper, we report the first InP–InGaAsP QWIP focal plane array (FPA). The 640 $times$ 512 FPA displayed remarkably low noise equivalent temperature difference (NETD) with very short integration times (46 mK at 66 K with ${T}_{rm int}=440 mu{hbox {s}}$ and f/1.5 optics). The results show that these QWIPs can be operated with high responsivity ($>$ 1 A/W) while offering bias adjustable gain in a wide range where the detectivity is almost constant at a reasonably high level.