Abstract
Defect structures in ZnO have been investigated with a first principle calculation using density functional theory combined with molecular dynamics theory for structural optimization. We calculated formation energy of native defects and impurities in ZnO to explain defect related phenomena observed in ZnO. In particular we paid attention to a deep donor level locating at about 0.3 eV below the bottom of conduction band, which level has been commonly detected in doped and undoped ZnO with deep level transition spectroscopy. From the results for isolated point defects, any possible origin for the deep donor level was not found. However, we found that some impurity complex is likely the origin for the 0.3 eV deep donor levelformed in ZnO.
