Small metal particles supported on titanium dioxide have attracted much interest due to the fundamental aspects of these interfaces but also due to several foreseen applications especially in catalysis and microelectronics [1,2]. However the stability of these surfaces under exposition to surrounding gases and to energy deposition [3] need a careful investigation. Indeed it can induce changes in the substrate as well as in the supported nanoclusters leading to drastic modifications in the surface behavior.
In this work the influence of energy deposition due both ion beam exposure and temperature will be considered for silver nanoparticles grown on TiO2(110) under UHV conditions. These effects were investigated by low energy ion scattering (LEIS), X-ray photoelectron spectroscopy (XPS) and secondary electron emission onset measurements.
Although these nanostructured surfaces are considered rather stable, experiments with ion impact may induce changes in the cluster growth mode [4]. At liquid nitrogen temperatures, an impinging ion beam appears to change the growth mode of the clusters from a 2D to a 3D growth mode. The energy transfer from the beam to nanoparticles can lead to an enhanced diffusion and restructuring. By comparing LEIS and XPS intensities as a function of ion fluence and substrate temperature attempts were done to quantify these effects. Coalescence induced by migration of nanoparticles on the surface that collide with neighbor clusters or atom transport inter nanoparticles are processes that can influence their growth and will be also addressed in this work.
[1] C.T. Campbell, Surf. Sc. Reports, 27(1997) 1 111
[2] U. Diebold, Surface Science Reports, 48 (2003) 53.
[3] O. M. N. D. Teodoro, A. M. C. Moutinho, Nucl. Instr. And Meth. B 222 (2004) 609
[4] H.P. Marques, A.R. Canário, A.M.C. Moutinho and O.M.N.D. Teodoro, to be published in Journal of Physics: Conference Series (JPCS) (2007).
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