Photoluminescence and dark current of p-doped InGaAs/AlxGa1-xAs strained multiple quantum wells

We report the temperature dependence of the photoluminescence spectra and current-voltage (I-d - V) characteristics of p-doped In0.15Ga0.85As/AlGaAs quantum well infrared photodetectors (QWIPs) with different barrier heights grown by molecular beam epitaxy (MBE). The dark current at low temperatures is found to be about three orders of magnitude lower than that reported for the n- and p-doped QWIPs made of other material systems. The PL spectra show two emission peaks which correspond to an intersubband absorption and are tunable by changing the mole fraction of Al. The low energy emission peak of the In0.15Ga0.85As/Al0.45Ga0.55As QWIP is found to be much lower in intensity than that of the high one, due possibly to excess Al which may result in defects or imperfection at/or near well-barrier interfaces. (C) 1996 Academic Press Limited