First-principles study of native point defects in ZnO

TLDR

The characterization of native point defects in ZnO remains debated, with inconclusive evidence on whether Zn interstitials or O vacancies dominate, a key issue for understanding and tailoring the material’s many technological applications. The study employs first‑principles pseudopotential calculations to determine the electronic structure, atomic geometry, and formation energy of native point defects in ZnO. The authors analyze interstitials, vacancies, and antisites in their relevant charge states and discuss the effects of dopants. The results indicate that Zn and O vacancies are the dominant defects in ZnO and propose a transition mechanism and defect center responsible for the experimentally observed green luminescence.

Abstract

The characterization of native point defects in ZnO is still a question of debate. For example, experimental evidence for ZnO with an excess of Zn is inconclusive as to whether the dominant defects are metal interstitials or oxygen vacancies. This information is essential to understand the behavior of the material and to tailor its numerous technological applications. We use the first-principles pseudopotential method to determine the electronic 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 also discussed. The results show that both the Zn and O vacancies are the relevant defects in ZnO. We also propose a possible transition mechanism and defect center responsible for the experimentally observed green luminescence.