Development of silicon nanowires based on Ag-Au metal alloy seed system for sensing technologies

Abstract

This paper shows the optimisation of the silicon nanowires (SiNWs) synthesis process and their features which are relevant for numerous sensing applications. In particular, the target was to design SiNWs substrate for surface-enhanced Raman spectroscopy (SERS). The majority of SiNWS has been synthesized by vapour-liquid-solid (VLS) method utilizing Au catalyst. However, in this paper, we show that Ag-Au catalyst system offers advantageous features such as a higher number of SiNWs per unit area, reduced SiNWs thickness and improved diameter distribution. The novel SERS sensor was tested utilizing Mercaptophenylboronic acid (MPBA) and compared with the traditional only Au catalysed system. Furthermore, the SiNWs features based on novel Ag-Au catalyst system were varied employing temperature, SiH4 partial pressure and deposition time. Axial and radial SiNWs growth rates and activation energies are determined and discussed.