Epitaxial growth of silver nanoislands on the surface of silicon nanowires in ambient air

Abstract

We study the epitaxial growth of Ag nanoislands on the surface of silicon nanowires (SiNWs) in ambient air by annealing SiNWs fabricated by metal-assisted chemical etching using Ag particles as the catalysts. We demonstrate that the nucleation of Ag on the surface of SiNWs is realized either by the direct decomposition of AgmO or by the reaction between AgmO and Si depending on the annealing temperature; AgmO is an adspecies with a lower effective detachment barrier, commonly introduced in oxygen-induced Ag surface migration systems. Along with the formation of Ag nanoislands, a thin layer of SiOx is formed on the outside surface of Ag nanoislands. The ambient-air epitaxial growth of Ag islands on the surface of SiNWs offers great flexibility in designing ideal metal contacts and Schottky barrier formation, and studying the electronic, magnetic and optical properties of the Si/Ag system. We also believe that SiNWs decorated by Ag nanoislands have many potential applications in plasmonic photovoltaic cells, surface-enhanced Raman spectroscopy detection and electronic devices.