Identification of an OH-Li center in ZnO: Infrared absorption spectroscopy and density functional theory

Abstract

The $2644.5\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}1}$ vibrational line observed in ZnO grown by the hydrothermal method and doped with D impurities is split into two components with intensities consistent with the natural abundances of $^{6}\mathrm{Li}$ and $^{7}\mathrm{Li}$, unambiguously establishing the direct involvement of Li in this center. Comparison with the results of density functional theory calculations strongly supports a structure with H bond-centered between Li and O along the $c$ axis. Because isotope splittings for elements heavier than Li will be more difficult to detect, this OH-Li center may be considered a unique model system for H trapped by impurities in ZnO.