Ab Initio Thermodynamics of Oxygen Vacancies and Zinc Interstitials in ZnO

Tor S Bjørheim; Eugene Kotomin

doi:10.1021/jz5018812

Ab Initio Thermodynamics of Oxygen Vacancies and Zinc Interstitials in ZnO

J Phys Chem Lett. 2014 Dec 18;5(24):4238-42. doi: 10.1021/jz5018812. Epub 2014 Nov 26.

Authors

Tor S Bjørheim¹, Eugene Kotomin^{2

3}

Affiliations

¹ †Centre for Materials Science and Nanotechnology, Department of Chemistry, University of Oslo, Norway, FERMiO, Gaustadallén 21, 0349 Oslo, Norway.
² ‡Max Planck Institute for Solid State Research, Heisenbergstrasse 1, 70569 Stuttgart, Germany.
³ §Institute for Solid State Physics, University of Latvia, Kengaraga 8, 1063 Riga, Latvia.

PMID: 26273968
DOI: 10.1021/jz5018812

Abstract

ZnO is an important wide band gap semiconductor with potential application in various optoelectronic devices. In the current contribution, we explore the thermodynamics of oxygen vacancies and zinc interstitials in ZnO from first-principles phonon calculations. Formation enthalpies are evaluated using hybrid DFT calculations, and phonons are addressed using the PBE and the PBE+U functionals. The phonon contribution to the entropy is most dominant for oxygen vacancies, and their Gibbs formation energy increases when including phonons. Finally, inclusion of phonons decreases the Gibbs formation energy difference of the two defects and is therefore important when predicting their equilibrium concentrations and the electrical activity of ZnO at finite temperatures.

Keywords: DFT; ZnO; defects; oxygen vacancy; phonons; thermodynamics; zinc interstitial.