Narrow-Band Type II Superlattice Photodetector With Detection Wavelength Shorter Than 2~μ m

We demonstrate that type II InAs/GaSb superlattice photodetector can reach the detection wavelength shorter than 2 μm by inserting AlSb barriers. The detector exhibits a narrow-band photoresponse feature (δλ/λ = 10.3%). At 77 K, the photoresponse maximum is at 1.84 μm and the Johnson noise limited detectivity is 1.1 × 1013Jones. We show that unlike a typical broad-band response feature using the interband transitions, for a p-i-n detector in the short wavelength range, a narrow-band response feature is the case, which is ascribed to the stronger absorption for the higher energy photons from the n region.