Synthesis and optical properties of silicon nanowires grown by different methods

We review our recent results on the growth and characterization of silicon nanowires (SiNWs). Vapourphase deposition techniques are considered, including chemical vapour deposition (CVD), plasma-enhanced chemical vapour deposition (PECVD), high-temperature annealing, and thermal evaporation. We present complementary approaches to SiNW production. We investigate the low-temperature (down to 300 ◦C) selective nucleation of SiNWs by Au-catalysed CVD and PECVD. Bulk production of SiNWs is obtained by thermalvapour deposition from Si/SiO powders in a high-temperature furnace. In this case, SiNWs grow either by condensing on Au catalyst films, or by self-condensation of the vapour in a lowertemperature region of the furnace. Finally, we also achieve controlled growth by thermolysis of nanopatterned, multilayered Si/Au thin-film precursors. The as-produced wires are compared in terms of yield, structural quality, and optical properties. Raman and photoluminescence spectra of SiNWs are discussed. PACS 81.15.Gh; 73.21.-b; 73.21.Hb; 71.20.Mq; 78.30.-j