Persistent photoconductivity and DLTS in indium-doped Cd0.9Mn0.1Te

The properties of an indium-related DX center were determined in indium-doped Cd-0.9 Mn0.1Te by deep-level transient spectroscopy (DLTS). These studies, carried out within a 77-360K temperature range, revealed the presence of five electron traps. It was possible to determine the activation energy for four of them. Their values were equal to 0.22-0.30, 0.43, 0.51 and 0.63 eV, respectively. For the first energy level, the concentration of the associated traps was higher than 10% of the concentration of the shallow levels and the capture cross section was thermally activated, with an energy barrier for capture equal to 0.1 eV. The concentration of the other three traps was lower than 10(14) cm(-3) Persistent photoconductivity was also observed at low temperatures. At 77 K, the photoconductivity continued for a very long time after the light was extinguished, and was present until the temperature of the sample increased to 170 K. The very high concentration and thermally activated capture cross section for the first trap suggest its DX center nature. (C) 1999 Elsevier Science B.V. All rights reserved.