TRAPPING PARAMETERS IN CDTE SINGLE-CRYSTALS DETERMINED BY THERMALLY STIMULATED CONDUCTIVITY

Thermally stimulated conductivity (TSC) data on high-resistivity, p-type CdTe single crystals are presented. The CdTe samples under study were either nominally undoped or doped with Mn or Fe. Deconvolution and peak fitting analysis of the TSC curves consistently revealed the presence of traps at approximately Ev+0.16, Ec-0.24, Ev+0.23, E v+0.32, Ev+0.39, Ev+0.40, and E v+0.47 eV in etched samples corresponding to TSC maxima at approximately 95, 110, 120, 145, 165, 170, and 190 K, respectively. An additional TSC peak, believed to be related to surface damage caused by mechanical polishing, is observed at approximately 105 K corresponding to electron traps at Ec-0.21 eV. The evidence indicates that the TSC curve from 80 to 200 K may be best described as a superposition of first-order (slow-retrapping) processes. Frequency factors and capture cross sections are calculated as temperature-dependent power-law functions. Some of the traps have been associated with particular defect structures, however, no clear correlation with the presence of Mn or Fe is observed.