High performance uncooled InAsSbP/InGaAs photodiodes for the 1.8-3.4μm wavelength range

Room temperature In,,,,Ga,,As photodiodes with an InAS(0.36)Sb(0.20)P(0.14) transparent window layer operating in the mid-infrared region over the wavelength range 1.8-3.4 mu m are reported. The InAs0.36Sb0.20P0.44/In0.97Ga0.03 As heterojunction photodiodes were grown on p-type (100) InAs substrates by liquid phase epitaxy (LPE). Basic detector characteristics have been measured and compared with other detectors in this wavelength range. The typical detectivity of the photodiodes is 1.2 x 10(10) cm Hz(1/2)/W at room temperature, which compares very favourably with that of TE cooled HgCdTe and is at least three times that of cooled PbSe photoconductors. The InAs0.36Sb0.20P0.44/In0.97Ga0.03 As hererojunction photodiodes offer the advantage of increased sensitivity and extended wavelength response at room temperature compared with that of currently available commercial photodetectors, making them an attractive alternative for a number of mid-infrared applications including optical gas sensors and infrared spectrometers. (C) 1997 Elsevier Science B.V.