title: Formation of isolated Zn vacancies in ZnO single crystals by absorption of ultraviolet radiation: a combined study using positron annihilation, photoluminescence, and mass spectroscopy.
abstract: Positron annihilation spectra reveal isolated zinc vacancy (V(Zn)) creation in single-crystal ZnO exposed to 193-nm radiation at 100 mJ/cm(2) fluence. The appearance of a photoluminescence excitation peak at 3.18 eV in irradiated ZnO is attributed to an electronic transition from the V(Zn) acceptor level at ~100 meV to the conduction band. The observed V(Zn) density profile and hyperthermal Zn(+) ion emission support zinc vacancy-interstitial Frenkel pair creation by exciting a wide 6.34 eV Zn-O antibonding state at 193-nm photon-a novel photoelectronic process for controlled V(Zn) creation in ZnO.
authors.affiliation: Department of Physics and Astronomy, Washington State University, Pullman, Washington 99164-2814, USA. enamul_khan@wsu.edu
authors.forename: Enamul H
authors.initials: EH
authors.lastname: Khan
authors.forename: Marc H
authors.initials: MH
authors.lastname: Weber
authors.forename: Matthew D
authors.initials: MD
authors.lastname: McCluskey