First-principles study on surface and interface properties of metal oxide and two-dimensional materials

Abstract

In this dissertation, the surface and interface of metal oxides and two-dimensional transition metal nanomaterials were investigated for their physical and chemical properties using first-principles calculations. First, the interface between Pt metal and TiO2 metal oxide, which is chemically bonded, was analyzed, and the reaction mechanism of oxygen gas and harmful gas was studied. It was proposed that oxygen vacancy in TiO2 support generate excess electrons, and that the electron transfer toward Pt may affect the properties of the Pt metal in contact and the surface gas reaction. Second, the interfacial properties of two-dimensional transition metal dichalcogenides, such as MoS2 and MoTe2, that physically interact with the tip and substrate were investigated. At the interface of physically weak bonds caused by van der Waals forces, the heat transport can be different depending on the unique phonon properties of each material. In addition, the atomic structure of the surface modifies the potential energy of interaction with the tip, resulting in a difference in the energy barrier experienced by the tip. This, in turn, is closely related to the magnitude of the friction force at the nanoscale.