Defect complexes formed with Ag atoms in CdTe, ZnTe, and ZnSe

Using the radioactive acceptor Ag-111 for perturbed gamma gamma-angular cor relation (PAC) spectroscopy for the first time, defect complexes formed wit h Ag are investigated in the II-VI semiconductors CdTe, ZnTe, and ZnSe. The donors In, Br and the Te-vacancy were found to passivate Ag accepters in C dTe via pair formation, which was also observed in In-doped ZnTe. In undope d or Sb-doped CdTe and in undoped ZnSe, the PAC experiments indicate the co mpensation of Ag accepters by the formation of double broken bond centres, which are characterised by an electric field gradient with an asymmetry par ameter close to eta = 1. Additionally, a very large electric field gradient was observed in CdTe, which is possibly connected with residual impurities . (C) 2000 Published by Elsevier Science B.V. All rights reserved.