GaInAsSb and InAsSbP photodetectors for mid-infrared wavelengths

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 pin 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 pin 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-JOLI*) of 5 X 10(10) cmHz(1/2)/W for GaInAsSb detectors and 4 x 10(9) cmHz(1/2)/W for InAsSbP have been measured. Room-temperature avalanche multiplication gain was measured for AlGaAsSb/GaInAsSb avalanche photodiodes.