title: Magnetic resonance identification of hydrogen at a zinc vacancy in ZnO.
abstract: Hydrogen (H) at a zinc vacancy (VZn) in ZnO is identified by electron paramagnetic resonance (EPR) and electron spin echo envelope modulation (ESEEM). In ZnO irradiated by 2 MeV electrons, a doublet EPR spectrum, labelled S1, is observed. The doublet structure and the accompanying weak satellites are shown to be the allowed and forbidden lines of the hyperfine structure due to the dipolar interaction between an electron spin S = 1/2 and a nuclear spin I = 1/2 of (1)H located at a VZn. The involvement of a single H atom in the S1 defect is further confirmed by the observation of the nuclear Zeeman frequency of (1)H in ESEEM experiments. We show that at a VZn, H prefers to make a short O-H bond with one O neighbour and is off the substitutional site, forming a low symmetry C1 defect. In this partly H passivated VZn, the unpaired electron localizes on the p orbital of another O neighbour of VZn, and not on the H.
authors.affiliation: Department of Physics, Chemistry and Biology, Linköping University, SE-581 83 Linköping, Sweden. son@ifm.liu.se
authors.forename: Nguyen Tien
authors.initials: NT
authors.lastname: Son
authors.forename: Junichi
authors.initials: J
authors.lastname: Isoya
authors.forename: Ivan G
authors.initials: IG
authors.lastname: Ivanov
authors.forename: Takeshi
authors.initials: T
authors.lastname: Ohshima
authors.forename: Erik
authors.initials: E
authors.lastname: Janzén
mesh_terms: D003624:Darkness; D004578:Electron Spin Resonance Spectroscopy; D004583:Electrons; D006859:Hydrogen / Q000032:analysis* / Q000737:chemistry*; D015032:Zinc / Q000737:chemistry*; D015034:Zinc Oxide / Q000737:chemistry*
chemical_list: D006859:Hydrogen; D015032:Zinc; D015034:Zinc Oxide