The investigation of Ag/ZnO interface system by first principle: The structural, electronic and optical properties

• Published in: Journal of solid state chemistry 2016-12, Vol.244, p.175-180
• Main Authors: Cheng, Hai-Xia, Wang, Xiao-Xu, Hu, Yao-Wen, Song, Hong-Quan, Huo, Jin-Rong, Li, Lu, Qian, Ping
• Format: Article
• Language: English
• Subjects: Ab-initio calculations; ABSORPTION SPECTRA; CRYSTAL DEFECTS; CRYSTAL LATTICES; DENSITY FUNCTIONAL METHOD; Electronic structure; EXPERIMENTAL DATA; INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; INTERFACES; MATERIALS SCIENCE; OPTICAL PROPERTIES; SILVER IONS; SURFACES; ZINC OXIDES
• ISSN: 0022-4596; 1095-726X
• DOI: 10.1016/j.jssc.2016.09.016

Ag/ZnO interfaces have been investigated for both of Zn-termination and O-termination by the first principle based on density functional theory. Our calculations demonstrate that the Ag atoms go inward from the Ag/ZnO interface, and the Zn and O atoms are all move outward bulk in the Zn-termination interface, and the changes are just opposite for O-termination. These behaviors are in agreement with the other studies in literatures. Furthermore, an expansion situation is observed in the first two Zn-O bilayer and first three Ag monolayers for both of Zn-termination and O-termination interfaces by comparing with the pure ZnO(0001) and Ag(111) surfaces. Moreover, the valence-band both of O-2p and Zn-3d states of Ag/ZnO interface gradual close to Femi level as the Zn, O atoms locate at the deeper layer for Zn-termination, but it is the other way round for O-termination. Calculated absorption spectrum indicates that the absorption intensity of Zn-termination interface is stronger than that of O-termination in the lower energy range (visible light region). These properties of ZnO surfaces are also evaluated for comparison with interfaces. The structures of Ag/ZnO interface: Zn-termination (left) and O-termination (right). In this Ag/ZnO interface system, the ZnO (0001) surface is rotated 30°(R30), and Ag (111) surface is built (2×2) supercell, then a (2×√3) R30 Ag/ZnO interface is constructed using the supercell method (i.e. periodically repeated slabs). The lattice mismatch of (2×√3) R30 Ag/ZnO (2.6% mismatch) is smaller than that of (1×1) Ag/ZnO (11% mismatch). [Display omitted]