High Operating Temperature InAs Quantum Dot Infrared Photodetector via Selective Capping Techniques

We report on the improvement in a quantum dot-in-a-well (DWELL) - based infrared photodetector's operating temperature with spectral response observable till 150 K. This improvement was achieved through addressing issues related with the growth conditions and subsequent capping of the quantum dots (QDs) by various overlying materials. The influence of these conditions was determined by examining the size and optical properties of the QDs as well as how it affected their function as the absorbing region in a DWELL IR photodetector. Photoluminescence of InAs QDs embedded in asymmetric InGaAs/GaAs quantum well or AlGaAs/InAlGaAs quantum well with different capping materials and different growth temperatures have been characterized as a function of the intermixing energies between the interface of the QDs and the capping materials. Through the improvement in QD confinement, the dark current can be decreased and the overall temperature of operation can be increased to 150 K.