Hydrogen at zinc vacancy of ZnO; An EPR and ESEEM study

ZnO中のZn空孔型欠陥の水素; EPR及びESEEMの研究

Son, N. T.*; 磯谷 順一*; Ivanov, I. G.*; 大島 武; Janzn, E.*

Son, N. T.*; Isoya, Junichi*; Ivanov, I. G.*; Oshima, Takeshi; Janzn, E.*

Defect centers in zinc oxide (ZnO) were investigated using electron paramagnetic resonance (EPR) techniques. Un-doped ZnO samples were irradiated with 2MeV electrons with fluence ranges between 2 and 410 /cm at room temperature. As a result of EPR measurements, the spectrum, labeled S1, with small-splitting doublet accompanied by weak satellites was observed. The obtained structure is shown to be the hyperfine structure because of the dipolar interaction between an unpaired electron spin and a nuclear spin of hydrogen (H). The presence of H atom in S1 was confirmed from the observation of the nuclear Zeeman frequency of H in electron spin echo envelope modulation experiments. Considering the observed spin-Hamiltonian parameters, S1 was identified to be the partly H-passivated Zn vacancy, VH, with the H ion making a short O-H bond with only one nearest O neighbor of V in the basal plane, being off the substitutional site, while the unpaired electron spin, by which the observed EPR signal increased, was localized on the p orbital of another O neighbor also in the basal plane.