Influence of the Surface Structure on the Growth of a Metallic Deposit on Oxide: Au/Al{sub}2O{sub}3 and Au/WO{sub}3

摘要

The structure, the composition, and the morphology of ceramic surfaces strongly influence their chemical, mechanical and electrical properties and play a major role in many technologically important processes such as corrosion, catalysis and sintering. They also affect the nature and strength of bonding at metal/ceramic interfaces in material growth on ceramic substrates. In this case, the initial state is known to play a dominant role on the overlayer properties. The aim of this paper is to evidence the role of the surface structure of an oxide substrate on the growth of a metal deposit. So we have studied the growth of gold deposit on well characterized Al{sub}2O{sub}3 α and WO{sub}3 surfaces. The surface structures are characterized by Reflection High Energy Electron Diffraction (RHEED), Transmission Electron Diffraction (TED) and Atomic Force Microscopy (AFM) and the deposit growth is investigated by Transmission Electron Diffraction (TED) and Transmission Electron Microscopy (TEM). Two different faces of Al{sub}2O{sub}3 have been investigated: (0001) and (1012) and for each face different surface structures have been found according to the annealing treatment. The WO{sub}3 substrates have been prepared as thin films with monoclinic structure and a (010) surface plane. The metal is deposited under vacuum onto the various surfaces from a Knudsen cell and we study the morphology, the granulometry and the structure of the deposits obtained on the different surfaces in the same growth conditions so that to investigate the influence of the substrate surface structure.