The Incorporation and Complex Formation of Ag Acceptors in CdTe

Abstract

AbstractUsing the radioactive isotope 111Ag, the incorporation of Ag into CdTe is investigated by photoluminescence spectroscopy (PL) and the perturbed yy-angular correlation technique (PAC). PL is used to demonstrate the incorporation as a substitutional acceptor (AgCd) by monitoring the intensity of the donor-acceptor transition, corresponding to an acceptor level of EV + 108 meV, which decreases just with the half life of the radioactive decay of the 111Ag isotope. Since the isotope 111Ag also serves as a probe atom for PAC experiments, it is possible to confirm the incorporation of Ag atoms on lattice sites with cubic symmetry. Additionally, in CdTe a defect complex is detected, which is assigned to a AgCd-VTe pair. A second defect complex is observed in CdTe doped with In, which is assigned to an InCd-AgCd pair. By PAC experiments with the probe 111In that are performed in Ag doped CdTe, the formation of the InCd-AgCd pair is confirmed besides the well known formation of the InCd-VCd pair. The migration energy of the cation vacancy is estimated on the basis of an isothermal annealing sequence.