2.4 µm cutoff wavelength AlGaAsSb/InGaAsSb phototransistors

The first AlGaAsSb/InGaAsSb phototransistors with a cutoff wavelength (50% of peak responsivity) of 2.4μm 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 2334A/W for λ=2.05μm at -20°C) and specific detectivity D* (up to 2.1 x 10 11 cmHz 1/2 /W for λ=2.05μm at -20°C).