2.4 /spl mu/m cutoff wavelength AlGaAsSb/InGaAsSb phototransistors

The first AlGaAsSb/InGaAsSb phototransistors with a cutoff wavelength (50% of peak responsivity) of 2.4 µm operating in a broad range of temperatures are reported. These devices are also the first AlGaAsSb/InGaAsSb heterojunction phototransistors (HPT) grown by molecular beam epitaxy (MBE). The new MBE-grown HPT exhibited both high responsivity R (up to 2334 A/W for λ=2.05 µm at−20°C) and specific detectivity D* (up to 2.1×1011 cmHz1/2/W for λ=2.05µm at −20°C).