Dominant hydrogen-oxygen complex in hydrothermally grown ZnO

Abstract

A hydrogen-related defect labeled as $\mathrm{H}\text{\ensuremath{-}}\mathrm{I}*$, observed in as-grown hydrothermal ZnO, is studied by means of infrared absorption spectroscopy. The defect possesses a stretch local vibrational mode at $3577.3\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}1}$ that is associated with a single hydrogen atom bound to oxygen with the $\mathrm{O}\ensuremath{-}\mathrm{H}$ bond oriented along the $c$ axis of the crystal. $\mathrm{H}\text{\ensuremath{-}}\mathrm{I}*$ can be destroyed only after anneal for several hours at $1200\phantom{\rule{0.2em}{0ex}}\ifmmode^\circ\else\textdegree\fi{}\mathrm{C}$. Possible microscopic models of $\mathrm{H}\text{\ensuremath{-}}\mathrm{I}*$ are discussed.