Normal-incident In/sub 0.2/Ga/sub 0.8/As/GaAs quantum well infrared photodetector employing a p-i-n-i-p camel diode structure

A normal-incident In/sub 0.2/Ga/sub 0.8/As/GaAs quantum well infrared photodetector (QWIP) utilizing the hole intersubband transitions having the detectivity as high as 4.4/spl times/10/sup 10/ cm Hz/sup 1/2//W has been demonstrated. The improvement in the detectivity is ascribed to the reduction in the dark current achieved by using a p-i-n-i-p camel diode structure. Further improvement in detectivity is expected by increasing the responsivity of the detector, which can be achieved by doping the quantum wells with a p-type dopant and increasing the period of MQW.