INGAALAS-INP QUANTUM-WELL INFRARED PHOTODETECTORS FOR 8-20-MU-M WAVELENGTHS

We demonstrate the first long-wavelength quantum-well infrared photode tectors using the lattice-matched n-doped InGaAlAs-InP materials syste m. Samples with AlAs mole fractions of 0.0, 0.1, and 0.15 result in cu toff wavelengths of 8.5, 13.3, and 19.4 mu m, respectively. A 45 degre es facet coupled illumination. responsivity of R = 0.37 A/W and detect ivity of D-lambda* = 3 x 10(8) cm .root Hz . W-1 at T = K, for a cutof f wavelength lambda(c) = 13.3 mu m have been achieved. Based on the me asured intersubband photoresponse wavelength, a null conduction band o ffset is expected for In0.52Ga0.21Al0.27As-InP heterojunctions.