Plasma-enhanced low temperature growth of silicon nanowires and hierarchical structures by using tin and indium catalysts

Plasma-enhanced low temperature growth (<300 ?C) of silicon nanowires (SiNWs) and hierarchical structures via a vapor-liquid-solid(VLS) mechanism are investigated. The SiNWs were grown using tin and indium as catalysts prepared by insitu Ho2 plasma reduction of SnO2 and ITO substrates, respectively. Effective growth of SiNWs at temperatures as low as 240 °C have been achieved, while tin is found to be more ideal than indium in achieving a better size and density control of the SiNWs. Ultra-thin (4-8nm) silica nanowires, sprouting from the dendritic nucleation patterns on the catalyst's surface, were also observed to form during the cooling process. A kinetic growth model has been proposed to account for their formation mechanism. This hierarchical structure combines the advantages of the size and position controllability from the catalyst-on-top VLS-SiNWs and the ultra-thin size from the catalyst-on-bottom VLS-ScNWs.