CuO/ZnO Nanocomposites Investigated by X-ray Photoelectron and X-ray Excited Auger Electron Spectroscopies

Abstract

Supported CuO/ZnO nanocomposites were prepared by a novel bottom-up approach, consisting of: i) deposition of columnar ZnO arrays on Si(100) by Plasma Enhanced-Chemical Vapor Deposition (PE-CVD) using a Zn(II) bis(ketoiminate) precursor; ii) Radio Frequency (RF)-sputtering of Cu in Ar atmospheres. Finally, ex-situ annealing was performed in air at 400 °C to promote a complete copper oxidation. The CuO/ZnO nanocomposites were characterised by Glancing Incidence X-ray Diffraction (GIXRD), Transmission Electron Microscopy (TEM), Field Emission-Scanning Electron Microscopy (FE-SEM) and Energy Dispersive X-ray Spectroscopy (EDXS), providing important information on their chemical, morphological and structural properties. In this contribution, a detailed investigation of a representative sample by X-ray Photoelectron (XPS) and X-ray Excited Auger Electron (XE-AES) Spectroscopies is presented, with particular attention to the analysis of O 1s, Zn 2p3/2 and Cu 2p core levels, as well as zinc and copper Auger signals.