First-principles study of native point defects in ZnO

Xerox Palo Alto Research Center, Palo Alto, California 94304~Received 18 January 2000!The characterization of native point defects in ZnO is still a question of debate. For example, experimentalevidence for ZnO with an excess of Zn is inconclusive as to whether the dominant defects are metal interstitialsor oxygen vacancies. This information is essential to understand the behavior of the material and to tailor itsnumerous technological applications. We use the first-principles pseudopotential method to determine theelectronic structure, atomic geometry, and formation energy of native point defects in ZnO. Interstitials,vacancies, and antisites in their relevant charge states are considered and the effects of dopants are alsodiscussed. The results show that both the Zn and O vacancies are the relevant defects in ZnO. We also proposea possible transition mechanism and defect center responsible for the experimentally observed greenluminescence.I. INTRODUCTION