Unambiguous identification of the PL-I9 line in zinc oxide

Abstract

Radioactive In111 atoms implanted into zinc oxide (ZnO) single crystals occupy substitutional Zn lattice sites after annealing to 700°C. The respective photoluminescence (PL) spectra of the samples were monitored while the donor In decayed into stable and isolectronic Cd. The commonly labeled PL-I9 line could be clearly assigned to excitons bound to the donor In. An arising luminescence band centered at 2.85eV was observed with the characteristic lifetime of the isotope, and the origin could be identified as levels of the isoelectronic Cd impurities.