Optical Characterization of Quantum-Dots-in-a-Well Infrared Photodetectors Under External Perturbations

In this project we have used Fourier transform infrared spectroscopy to study the photoresponse of two different types of quantum dot-in-a-well infrared photodetectors (DWELL QDIPs). The basic task was to compare the photoresponse of these two detectors, and to study the influence of external resonant laser pumping on the photoresponse. Series of measurements were done at 77K. In the first measurements we investigated the photoresponse for different applied voltages at 77K. In a second run of experiments, we used a 1064 nm infrared semiconductor laser to resonantly pump the fundamental transition of the quantum dots. The results show that by using this additional illumination the photoresponse was dramatically increased by creating additional charge carriers in the quantum dots. This could be used to increase the sensitivity of infrared detectors based on QDs