Very long wavelength infrared type-II detectors operating at 80 K

Abstract

We report a demonstration of very long wavelength infrared detectors based on InAs/GaSb superlattices operating at $\text{T=80\hspace{0.05em}}\mathrm{K}.$ Detector structures with excellent material quality were grown on an optimized GaSb buffer layer on GaAs semi-insulating substrates. Photoconductive devices with 50% cutoff wavelength of ${\lambda }_{\mathrm{c}}\text{=17\hspace{0.05em}μ}\mathrm{m}$ showed a peak responsivity of about 100 mA/W at $\text{T=80\hspace{0.05em}}\mathrm{K}.$ Devices with 50% cutoff wavelengths up to ${\lambda }_{\mathrm{c}}\text{=22\hspace{0.05em}μ}\mathrm{m}$ were demonstrated at this temperature. Good uniformity was obtained over large areas even for the devices with very long cutoff wavelengths.