GaInAsSb and InAsSbP photodetectors for mid-infrared wavelengths

Abstract

Recent improvements in mid-infrared photodetectors fabricated by the liquid phase epitaxial growth of GaInAsSb, InAsSbP, and AlGa(As)Sb on GaSb and InAs substrates are reported. GaInAsSb and InAsSbP p/n detector and AlGaAsSb/GaInAsSb avalanche photodiode (APD) structures have been fabricated. Results from previously reported devices were improved by the addition of high bandgap window layers for GaInAsSb detectors and a new longer-wavelength composition for InAsSbP detectors. Preliminary results indicate that these devices can have higher detectivity with lower cooling requirements than commercially available detectors in the same wavelength range. Infrared p/n junction detectors made from GaInAsSb and InAsSbP showed cut-off wavelengths of 2.3 mu m and 3.2 mu m respectively. Room temperature Johnson noise-limited detectivities (D*/sub JOLI/) of 5*10/sup 10/ cmHz/sup 1/2 //W for GaInAsSb detectors and 4*10/sup 9/ cmHz/sup 1/2 //W for InAsSbP have been measured. Room-temperature avalanche multiplication gain was measured for AlGaAsSb/GaInAsSb avalanche photodiodes.