Shaping Ag clusters on Titania

Abstract

We present a study of the growth of silver clusters on a TiO 2(110) substrate in ultrahigh vacuum. The growth is monitored in situ by Low Energy Ion Scattering (LEIS) using He+ scattering and X-ray Photoelectron Spectroscopy (XPS) and ex situ by scanning electron microscopy (SEM). Experimental results show that the deposition rate, the substrate temperature and the annealing temperature are key parameters for controlling the size and morphology of the Ag clusters. By changing the deposition rate, the mean cluster diameter can vary from 5 to 20 nm. The growth of Ag at low substrate temperature shows a transition from quasi 2D flat islands to a 3D growth mode at submonolayer coverage. The substrate was annealed at different temperatures and the clusters shape controlled from a quasi 2D flat island to 3D sharp islands with a maximum substrate exposure, prior to cluster desorption. © 2007 IOP Publishing Ltd.