摘要：Defect energetics, charge transition levels, and electronic band structures of several Cl-related complexes in CdTe are studied using density-functional theory calculations. We investigate substitutional chlorine (Cl Te and Cl Cd ) and complexes formed by Cl Te with the cadmium vacancy (Cl Te -V Cd and 2Cl Te -V Cd ) and the Te Cd antisite (Cl Te -Te Cd ). Our calculations show that none of the complexes studied induce deep levels in the CdTe band gap. Moreover, we find that Cl Te -V Cd and Cl Te are the most stable Cl-related centers in n-type and p-type CdTe, under Te-rich growth conditions, showing shallow donor and acceptor properties, respectively. This result suggests that the experimentally-observed Fermi level pinning near midgap would be originated in self-compensation. We also find that the formation of the Cl Te -Te Cd complex passivates the deep level associated to the Te antisite in neutral charge state.
