Photo-induced current transient spectroscopy (PICTS) of deep levels in electrodeposited CdTe films

The PICTS technique in conjunction with a highly absorptive excitation wavelength is used to characterize and to distinguish the electron and hole traps in electrodeposited CdTe films. All the deep levels measured are within two deep (donor-type and acceptor-type) energy bands and are related to only native defects and their complexes with chlorine. Except chlorine, no other trace-impurity levels could be detected, implying the effectiveness of electropurification of the bath solution prior to deposition of CdTe. Some results related to the effect of different annealing processes on the spectrum of deep levels are also discussed.