Single phase formation of Co-implanted ZnO thin films by swift heavy ion irradiation: Optical studies

Low temperature photoluminescence and optical absorption studies on 200 MeV Ag+15 ion irradiated Co-implanted ZnO thin films were studied. The Co clusters present in as implanted samples were observed to be dissolved using 200 MeV Ag+15 ion irradiation with a fluence of 1x10(12) ions/cm(2). The photoluminescence spectrum of pure ZnO thin film was characterized by the I-4 peak due to the neutral donor bound excitons and the broad green emission. The Co-doped ZnO films show three sharp levels and two shoulders corresponding to 3t(2g) and 2e(g) levels of crystal field splitted Co d orbitals, respectively. The ultraviolet-visible absorption spectroscopy also shows the systematic variation of band gap after 200 MeV Ag+15 ion irradiation. (c) 2006 American Institute of Physics.