Size distribution of silver nanoclusters induced by ion, electron, laser beams and thermal treatments of an organometallic precursor L. D’Urso a,* , V. Nicolosi b , G. Compagnini a , O. Puglisi a a Dipartimento di Scienze Chimiche, Universita ` di Catania, Viale A. Doria 6, 95125 Catania, Italy b Molecular Electronics & Nanotechnology, Department of Physics, Trinity College, The University of Dublin, Dublin 2, Ireland Abstract Recently, a huge variety of physical and chemical synthetic processes have been reported to prepare nanostructured materials made of very small (diameter < 50 nm) metallic clusters. Depending on the nature of clusters, this new kind of materials posses interesting properties (electronic, optical, magnetic, catalytic) that can be tailored as a function of the particles size and shape. Silver nanoparticles have been obtained by direct thermal treatment or by beam-enhanced decomposition (ion, electron and laser) of a silver organometallic compound (precursor) spinned onto suitable substrates. In this paper, we present the results of a study on the size distribution of such nanoparticles as a function of the different synthesis methods. It was found that the methods employed strongly affect the silver nanoparticles formation. Smaller silver nanoclusters were obtained after reduction by ion beam irradiation and thermal treatment, as observed by using different techniques (AFM, XRD and UV-Vis). # 2003 Published by Elsevier B.V. PACS: 73.50.M; 68.65; 78.66.B Keywords: Silver nanoclusters; Organometallic compound; Optical properties 1. Introduction In the last few years, metal nanoparticles have attracted the attention of an increasing number of researchers from several disciplines. The nanoparti- cles size, between the molecular and bulk solid state structures, is responsible for the anomalous properties (electronic, optical, electrical, magnetic, chemical, catalytic and mechanical) of these materials and makes them suitable for new applications in the fields of catalysis, microelectronics, and optoelectronics. Some of the most important properties are: the lower effective Debye temperature [1–3], the increased solid–solid transition pressure [4], the higher self- diffusion coefficient [5], the higher thermal diffusivity [6], and a variety of optical dispersion and nonlinear effects [7]. It is also attracting the possibility to control the properties of these materials by changing their shape, size and distribution [8]. Hence, it is very important to have the possibility to develop and optimize preparation techniques that can control these parameters. At present, materials containing metal nanoparticles are synthesized with a large vari- ety of chemical or physical methods giving the pos- sibility to control their macroscopic and microscopic structure. In previous papers [9–12], we discussed a Applied Surface Science 226 (2004) 131–136 * Corresponding author. Tel.: þ39-095-7385-129; fax: þ39-095-580138. E-mail address: ldurso@dipchi.unict.it (L. D’Urso). 0169-4332/$ – see front matter # 2003 Published by Elsevier B.V. doi:10.1016/j.apsusc.2003.11.012