Nucleation and growth of gold nanoparticles deposited by RF-sputtering: an experimental study
- PDF / 404,700 Bytes
- 6 Pages / 595 x 842 pts (A4) Page_size
- 55 Downloads / 167 Views
M3.7.1
Nucleation and growth of gold nanoparticles deposited by RF-sputtering: an experimental study Davide Barreca1, Alberto Gasparotto2, Elisabetta Pierangelo2 and Eugenio Tondello2 ISTM-CNR and INSTM - Department of Chemical Sciences - Padova University - Via Marzolo, 1 - 35131 Padova (Italy). 2 Department of Chemical Sciences and INSTM - Padova University - Via Marzolo, 1 - 35131 Padova (Italy). 1
ABSTRACT Gold nanoparticles were deposited on SiO2, Si(100) and HOPG (Highly Oriented Pyrolitic Graphite) by RF-sputtering from Ar plasmas. Sample preparation was performed at temperatures as low as 60°C under different total pressures, RF-powers and deposition times, with particular attention to the influence of process parameters and growth surface on nanosystem properties. In this paper, the most important results regarding the compositional, structural and morphological features of the obtained specimens, are presented and discussed. INTRODUCTION Gold nanoparticles supported on various substrates have received an increasing attention for both fundamental and applicative purposes. In the former case, many research activities have been aimed at understanding the processes involved in the transition from free atoms to bulk metal [1,2]. In the latter, a great interest has mainly been devoted to heterogeneous catalysis [3,4] and microelectronics [5]. As a general rule, the chemico-physical properties of these composite materials are strongly dependent on the size and shape of gold nanoparticles, as well as on metalmetal and metal-substrate interactions [6,7]. These characteristics can be easily controlled by plasma-assisted techniques such as RF-sputtering, thanks to the soft synthetic conditions and to the competition between deposition/ablation processes characterizing glow-discharges. The latter feature might allow the preparation of nanosystems with tailored properties, provided that a suitable choice of processing conditions is made. This work is part of an extensive research activity aimed at the preparation of Au-based nanosystems obtained by gold dispersion both on conventional substrates and on porous matrices. In particular, in the present case, Au nanoparticles were deposited on SiO2, Si(100) and HOPG by RF-sputtering in Ar plasmas. All experiments were carried out at a substrate temperature as low as 60°C, in order to minimize the contribution of thermal effects with respect to plasma–dependent phenomena. In particular, the role of the applied RF-power, total pressure and deposition time on system composition, nanostructure and morphology was investigated. To this aim, both in-situ and ex-situ characterization techniques were employed. While LRI (Laser Reflection Interferometry) was used for a real-time monitoring of growth processes, XPS (X-ray Photoelectron Spectroscopy) and GIXRD (Glancing Incidence X-ray Diffraction) yielded information on the dependence of gold amount and crystallite size on synthesis conditions. Finally, a valuable insight on the surface topography was obtained by AFM (Atomic Force M
Data Loading...
