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

Abstract

Plasma-enhanced low temperature growth (<300 °C)of silicon nanowires (SiNWs) and hierarchical structures via a vapor–liquid–solid (VLS) mechanismare investigated. The SiNWs were grown using tin and indium as catalysts prepared by in situ H2 plasmareduction of SnO2 and ITO substrates, respectively. Effective growth of SiNWs at temperatures as low as240 °C have been achieved, while tin is found to be more ideal than indium in achieving a bettersize and density control of the SiNWs. Ultra-thin (4–8 nm) silica nanowires, sprouting fromthe dendritic nucleation patterns on the catalyst’s surface, were also observed toform during the cooling process. A kinetic growth model has been proposed toaccount for their formation mechanism. This hierarchical structure combinesthe advantages of the size and position controllability from the catalyst-on-topVLS–SiNWs and the ultra-thin size from the catalyst-on-bottom VLS–ScNWs.