Mid infrared quantum dots in a well infrared photodetectors

The design, growth, fabrication and characterization of novel InAs/ InGaAs quantum dots-in-a-well (DWELL) infrared photodetectors are presented. These detectors, in which the active region consists of InAs quantum dots embedded in an InGaAs quantum well, represent a hybrid between a conventional quantum well infrared photodetector (QWIP) and a quantum dot infrared photodetector (QDIP). Like QDIPs, the DWELL detectors display normal incidence operation without gratings or optocouplers while demonstrating reproducible "dial-in recipes" for control over the operating wavelength, like QWIPs. Moreover, the DWELL detectors also have demonstrated bias-tunability and multi-color operation in the mid wave infrared (MWIR, 3-5 μm), long wave infrared (LWIR, 8-12 μm) and very long wave infrared (VLWIR, >14 μm) regimes. We have recently realized LWIR 320×256 focal plane arrays (FPAs) operating at liquid nitrogen temperatures.