IN SITU PHOTOELECTRON SPECTROSCOPY INVESTIGATION OF INTERFACE COUPLING BETWEEN METALS AND MoO3 THIN FILMS

Abstract

Metal nanoparticles or nanoclusters have been widely used to functionalize semiconductor metal oxide nanostructures-based gas sensors or photodetectors to significantly enhance the device performance. It is crucial to reach a thorough understanding of the interfacial coupling between the metal nanoclusters and the metal oxide nanostructures. Here, in situ X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS) have been used to investigate the interfacial interactions between metals (Au and Co) and molybdenum trioxide (MoO3) films. In spite of the high work function ([Formula: see text]6.8[Formula: see text]eV) of the thermally evaporated MoO3 films, only weak interaction is observed at the Au/MoO3 interface. Au clusters or films can remain their neutral and nonchemically reacted state on MoO3 film. In contrast, the interfacial chemical reaction between Co and MoO3 is significantly strong. A band-bending in MoO3 and two interface states have been observed at the Co/MoO3 interface.