Silicon nanowires prepared by hydrogen-assisted rf-magnetron sputtering on bismuth-coated ITO glass

Silicon nanowires (SiNWs) have been grown on ITO glass substrates at a low temperature (260 °C) using a Bismuth (Bi) catalyst coating with a thickness of 50 nm via hydrogen-assisted rf-magnetron sputtering deposition. The growth conditions of SiNWs including substrates temperature and flow ratio of hydrogen (H2)/argon (Ar) have been studied in details. As the growth temperature and flow ratio increases from 260 to 400 °C and from 15/85 to 45/55 respectively, the density and average length of SiNWs present a non-monotonic variation. The synthetic SiNWs are disorderly oriented on ITO glass substrates with an average length of 1.2 µm for a 60 min deposition process and at a flow ratio of H2/Ar (25/75). The synthesized mechanism of SiNWs is interpreted by means of the vapor-liquid-solid (VLS) mechanism. The Raman spectra indicates that the SiNWs are comprised of amorphous and nanocrystalline silicon, and the volume fraction of the crystallized SiNWs reduces rapidly with increasing the growth temperature.