Interband cascade type-II infrared InAs/GaSb - current status and future trends

Abstract

Type-II InAs/GaSb interband supperlattice cascade infrared detectors (IB CIDs) proved to be promising candidate for short response time devices operating in room and higher temperatures. The spectral responsivity of mid-wave (MWIR) T2SLs InAs/GaSb based IB CID has been observed even up to 380 K. Short time constant (τs) is directly related to the unique carrier transport properties of the IB CID structures, where at 380 K ~ 4 ns τs was observed. What is more, thermal generation recombination rates of IB CIDs are orders of magnitude reduced in comparison with corresponding intersubband quantum cascade infrared detectors (IC QCID) giving flexibility in higher operating temperature (HOT) applications. The most important feature is that the multiple-stage architecture is useful for improving the sensitivity of HOT detectors, where the quantum efficiency is limited by short diffusion length. Assuming that absorption depth for IR radiation is longer than the diffusion length, only a limited portion of the photogenerated carriers contribute to the quantum efficiency. That could be circumvented by fabrication of multi-stage devices where each equal stage consist of active, relaxation and barrier layers. IB CID T2SLs InAs/GaSb detector operating at 380 K exhibits Johnson noise limited detectivity at the level of ~ 108 Jones without implementation of immersion lens. In this paper the current status of novel HOT T2SLs InAs/GaSb IB CID is presented. Analysis of the detector’s performance versus bias voltage and operating temperatures and future trends in development of the quantum cascade detectors are shown. The paper focuses on development of IR HOT detectors and potential approaches related to materials - T2SLs InAs/GaSb where IB CIDs that eliminate the cooling requirements of IR photodetectors operating in MWIR range are presented. The prediction of near future impact of that technology on infrared detector development is also shown.