| Multispectral infrared photodetectors have many applications in both civilian and defense related application. A quantum dot infrared photodetector that consists of vertically-stacked InAs quantum dots layers has been developed. The detection bands have were designed with capping layers of GaAs and In 0.15Ga0.85As for near longwave infrared (NLWIR, 6-8 mum) and longwave infrared (LWIR, 8-12 mum) bands, respectively. Voltage-tunable single or dual band operations were demonstrated with over ten times photoresponsivity and photodetectivity D* differentiation. Since each of the detection hands can be designed individually and then stacked. Vertically-stacked QDIP structures offer flexibility in detection band engineering and allows easy control of detection hands. The vertically stacked structure can be readily scaled up for multi-band detection. |
