InAs/GaSb superlattices for photodetection in short wavelength infrared range

The first report of a short wavelength infrared detector based on type II InAs/GaSb superlattices is presented. Very short period superlattices containing InAs (2ML)/GaSb (8ML) superlattices (SLs) were grown by molecular-beam epitaxy on GaSb substrates. The photoluminescence showed a cut-off wavelength at 2.1 μm at 10 K and 2.6 μm at 300 K. Room-temperature optical transmittance spectra shows obvious absorption in InAs (2ML)/GaSb (8ML) SL in the range of 450–680 meV, i.e. 1.8–2.7 μm. The cut-off wavelength moved from 2.3 μm to 2.6 μm with temperature rising from 77 K to 300 K in photoresponse spectra. The blackbody response Rv exponentially decreased as a function of 1/T in two temperature sections (130–200 K and 230–300 K). The blackbody detectivity D bb ∗ was beyond 1 × 108 cmHz1/2/W at room temperature.