Effects of annealing on the spectral response and dark current of quantum dot infrared photodetectors

We report on a detailed analysis of the dark currents of a quantum dot infrared photodetector annealed at various temperatures from 700 to 850 deg. C. Annealing induced intermixing of the quantum dot and barrier material and therefore a reduction of the quantum dot confining potential, which caused a shift in the spectral response from 7 to 9.3 μm for an 850 deg. C anneal. An analysis of the dark currents reveals that the dark current mechanisms are similar for the annealed and as-grown devices, indicating that annealing up to 850 deg. C may not have an adverse effect on the semiconductor material quality.