Study of oxygen vacancies' influence on the lattice parameter in ZnO thin film

Undoped ZnO film was obtained at ambient temperature using magnetron sputtering and further annealed in vacuum and oxygen atmosphere. A (103) texture was observed on the surface of as-deposited (002)-preferred ZnO film. XPS shows that the majority zinc remains in the valence state of Zn2+, meanwhile the close inspection of O 1s shows that O 1s is composed of components including O-I, O-II and chemically- or physically-adsorbed oxygen. By the relative intensity of O-I/O-II and broadened O-I the oxygen vacancy concentration variation was considered in different annealing processes. Since the Zn atoms are mostly located in the ZnO1-x matrix, the (002) peak shift in the XRD of the vacuum- and oxygen-annealed films is attributed to the variation of the oxygen vacancy concentration, suggesting that the oxygen vacancies in the ZnO thin films are responsible for the decrease of the lattice parameters. (c) 2012 Elsevier B.V. All rights reserved.