Tuning in spectral response due to rapid thermal annealing on dot-in-a-well infrared photodetectors

Here we investigated the effect of post-growth rapid thermal annealing (RTA) on dot-in-a-well infrared photodetectors. In a photoluminescence (PL) study, we initially observed a small red shift in the ground-state PL peak upon annealing to 650 degrees C but then saw the usual blue shift as the annealing temperature increased. We also observed increases in the dark current as the annealing temperature increased up to 700 degrees C but a sudden decrease in the dark current at 750 degrees C. Activation energy is calculated using temperature-dependent PL and dark current measurements. The photoresponse peak was observed at 6.41 mu m for the as-grown device. As we increased the annealing temperature to 800 degrees C, the peak response shifted to 9.52 mu m. Thus, we achieved wavelength tunability of peak photoresponse using the post-growth annealing technique. (C) 2013 Elsevier Ltd. All rights reserved.