Dewetting process of Au films on SiO 2 nanowires: Activation energy evaluation F. Ruffino a,b,n , M.G. Grimaldi a,b a Dipartimento di Fisica e Astronomia, Università di Catania, via S. Sofia 64, 95123 Catania, Italy b Center for Materials and Technologies for Information Communication and Solar Energy (MATIS CNR-IMM), via S. Sofia 64, 95123 Catania, Italy HIGHLIGHTS  SiO 2 nanowires are produced di- rectly on a Si surface.  The SiO 2 nanowires are coated by Au films.  The Au films are transformed in na- noparticles by thermal-induced de- wetting processes.  The activation energy for the de- wetting process of Au films on SiO 2 nanowires is evaluated. GRAPHICAL ABSTRACT article info Article history: Received 5 November 2014 Received in revised form 24 December 2014 Accepted 21 January 2015 Available online 22 January 2015 Keywords: SiO 2 nanowires Au nanoparticles Sputtering deposition Dewetting Activation energy abstract SiO 2 nanowires gain scientific and technological interest in application fields ranging from nano-elec- tronics, optics and photonics to bio-sensing. Furthermore, the SiO 2 nanowires chemical and physical properties, and so their performances in devices, can be enhanced if decorated by metal nanoparticles (such Au) due to local plasmonic effects. In the present paper, we propose a simple, low-cost and high-throughput three-steps methodology for the mass-production of Au nanoparticles coated SiO 2 nanowires. It is based on (1) production of the SiO 2 nanowires on Si surface by solid state reaction of an Au film with the Si substrate at high tem- perature; (2) sputtering deposition of Au on the SiO 2 nanowires to obtain the nanowires coated by an Au film; and (3) furnace annealing processes to induce the Au film dewetting on the SiO 2 nanowires surface. Using scanning electron microscopy analyses, we followed the change of the Au nanoparticles mean versus the annealing time extracting values for the characteristic activation energy of the dewetting process of the Au film on the SiO 2 nanowires surface. Such a study can allow the tuning of the nanowires/ nanoparticles sizes for desired technological applications. & 2015 Elsevier B.V. All rights reserved. 1. Introduction SiO 2 nanowires (NWs) gain scientific and technological interest due to their intensive blue light emission [1], one-dimensional luminescence properties [2], and wave-guiding characteristic [3], making them candidates for applications in application in fields ranging from nano-electronics, optics and photonics to bio-sensing [1–6]. SiO 2 NWs are, nowadays, routinely produced by sol–gel based approaches, thermal evaporation or chemical vapor de- positions, and laser ablation based methods [7–10]. In general, such methodologies are expensive, requiring complex sequences (so, hard to engineering) of process, or require harmful gases like silane. However, recently, a simple and versatile solid state reaction based method was developed for the large area production of SiO 2 NWs on surfaces [11–18]; it is based on a solid-state reaction of Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/physe Physica E http://dx.doi.org/10.1016/j.physe.2015.01.033 1386-9477/& 2015 Elsevier B.V. All rights reserved. n Corresponding author at: Dipartimento di Fisica e Astronomia, Università di Catania, via S. Sofia 64, 95123 Catania, Italy. Fax: þ39 0953785243. E-mail address: francesco.ruffino@ct.infn.it (F. Ruffino). Physica E 69 (2015) 121–126