Studies of the mechanism of electrical conduction in As-doped ZnO by structural and chemical-bonding analyses and first principle calculations

X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and first-principle density-functional theory (DFT) calculations are carried out on the p-type As-doped ZnO (ZnO:As) films prepared by pulsed laser deposition (PLD). XRD results indicate that defects are induced by As incorporation in ZnO lattice structure. The XPS analyses demonstrate that As atoms locate Zn-sites in ZnO:As films. Based on XRD and XPS results, it can be suggested that some forms of As-Zn (As occupies Zn site) related complexes construct acceptors. First-principle density-functional calculations can show the electronic structures of several possible As-Zn-related complexes in ZnO:As. The calculation results show that an As-Zn-2V(Zn) (an As atom occupies a Zn site and induces two nearby Zn vacancies) complex can be a shallow acceptor in ZnO. (C) 2008 Elsevier Ltd. All rights reserved.