Hydrogen-Induced Defects of Subsurface Layer in ZnO Single Crystal Probed by a Slow Positron Beam

Abstract

Hydrogen-induced defects of ZnO single crystals electrochemically charged with hydrogen have been investigated by positron beam-based Doppler broadening spectroscopy, X-ray diffraction (XRD) and optical microscopy (OM). XRD and OM results indicated that a deformation layer was formed due to hydrogen-induced structural change at the subsurface of ZnO single crystal. Slow positron beam measurements showed that this deformation layer contained many defects, such as dislocations and Zn vacancies, which led to increase of S parameter.