Preferentially oriented thin-film growth of CuO(111) and Cu2O(001) on MgO(001) substrate by reactive dc-magnetron sputtering

摘要

Copper oxide films deposited on MgO(001) substrates by reactive magnetron sputtering under the metal-mode condition were studied by X-ray diffraction (XRD) and reflection high-energy electron diffraction (RHEED) analyses for structural analysis, and X-ray-excited Auger electron spectroscopy (XAES) for chemical bonding analysis. CuO(111) thin films grew from their initial growth stage maintaining the same crystallinity on MgO(001) substrates at 400 degrees C. When the substrate temperature was increased to 600 degrees C, the assputtered films comprise Cu(001), amorphous Cu2O phase, and Cu2O(001) phase. The Cu(001) phase was observed at initial growth stage. This is probably because O-2 gas molecules could not sufficiently stick to the MgO substrate at 600 degrees C. Single phase of Cu2O(001) was obtained by the cooling of the as-sputtered films in O-2 atmosphere. The growth of single phase Cu2O(001) is considered as a solid-phase heteroepitaxial growth on MgO(001) surface, which was caused by incorporating O-2 gas into the as-sputtered films. (c) 2006 Elsevier Ltd. All rights reserved.