Mid-wave infrared interband cascade photodetectors and focal plane arrays

The Interband Cascade (IC) detector with InAs/Ga(In) Sb type-II superlattice (T2-SL) absorbers is a new type of high-performance infrared photodetector that has many unique features. In this IC detector design, the T2-SL absorber is sliced into multiple thinner segments that are sandwiched between electron and hole barriers, forming one stage. Multiple stages are electrically connected in series. The asymmetric energy-band alignment and ultra-fast carrier transport channel have enabled IC detectors to operate under/near zero-bias. The large lifetime contrast and the great design flexibility make IC detectors very suitable for high temperature operations. Our effort has led to the demonstration of mid-IR single pixel devices operating up to 450 K under zero-bias. These devices achieved superior electrical performance compared to HgCdTe technology at higher operation temperatures. In this presentation, we will discuss the new developments of low-noise mid-IR IC photodetectors and their focal plane arrays. Device studies on the influence of design on their optical and electrical performance will be discussed, and the most recent technical progress is also reported.