First-principles study of the rectifying properties of Au/SnO2 interface

Based on the first-principles calculations, we investigate the properties of Au contacts, surface structure, and band bending for Au/SnO2(1 0 1) and Au/SnO2(1 0 0) contacts under different conditions. Our results show that the Schottky barrier height (SBH) strongly depends on the interface structure. A stoichiometric Au/SnO2(1 0 1) interface forms a Schottky contact, while Au/SnO2(1 0 0) exhibits ohmic contact characteristics. When oxygen vacancy (VO) is present in the interfacial SnO2 layer, the Fermi level shifts up to the conduction band minimum, resulting in a smaller SBH. Although Au contact on SnO2(1 0 1) with VO has non-Schottky properties, it gains Schottky properties after doping with a low-valence element. In addition, the SBHs of each interface structure are different, indicating that the modulation effect of SBH mainly depends on the rearrangement of interfacial potentials caused by the different interface structures. Such a rearrangement causes corresponding changes in the energy band at the interface, resulting in different SBHs.