Intersubband Transitions in Quantum Wells Infrared Photodetector

Over the past two decades, infrared detection has become an important application. There have been many theoretical and experimental studies focused on the intersubband transitions in multiple quantum well systems. We report on the two-color multiple quantum well infrared photodetector. The reported detector consists of two stacks of InGaAs wells and AlGaAs barriers grown on semi-insulating GaAs substrate for mid-wavelength infrared detection. The photoresponse was measured and analyzed on this device, which confirm presence of the intersubband transitions at 6.3 mum and 5.5 mum. In addition, the transfer matrix method is used to estimate the peak position energies of the intersubband transitions in the two stacks. Furthermore, the temperature dependence of photoresponse was measured under a bias voltage of -2.5V. The photoresponse was remained observable at temperature as high as 110K.