Trap detection at A p-p In0.53Ga0.47As/InP heterojunction by means of C-V, I-V and photocapacitance measurements

Abstract We report our investigations on LPE grown p-p InGaAs/InP heterojunctions by means of C − V , I − V and photocapacitance measurements. At 77 K we calculate a valence band offset of 0.47 eV and a fixed interface charge of 5x10 11 cm -2 . The acceptor-like trap levels at 0.37, 0.40 and 0.56 eV, and the donor-like trap level at 0.39 eV are located at the InGaAs side of the heterojunction. At the InP side we detect a donor-like trap level at 0.47 eV. Under illumination photogenerated holes create an additional charge in the hole accumulation layer at the heterointerface. We calculate an additional sheet carrier concentration of 4x10 10 cm -2 at 0.4 eV illumination level and 8.4x10 10 cm -2 sheet carrier concentration at 0.6 eV illumination level. The first and second sheet charges are caused by ionization of the acceptor level at 0.40 and 0.56 eV, respectively. At 300 K, C - V profiles measured under daylight show an increasing hole accumulation layer at the InGaAs side of the heterojunction and an increasing hole depletion layer at the InP side with decreasing measuring frequency.