Electronic properties of deep levels in p-type CdTe

Abstract
DLTS and associated electrical measurements were made on unintentionally doped CdTe crystals obtained from several vendors, on Cu-doped CdTe, and on Te-annealed CdTe. All of the crystals were p-type. Four majority carrier deep levels were observed in the temperature range from 100–300 K with activation energies relative to the valence band of 0.2, 0.41, 0.45, and 0.65 eV. Two of these levels were specific to certain crystals while the other two were seen in every sample and are attributed to common impurities or native defects. Fluctuations in the concentrations of levels across samples and as a result of modest sample heating (400 K) were also observed.