No CrossRef data available.
Published online by Cambridge University Press: 17 March 2011
For several decades, the vapor-liquid-solid (VLS) process,1,2 where gold particles act as a mediating solvent on a silicon substrate, forming a molten alloy, has been applied to the generation of silicon whiskers. The diameter of the whisker is established by the diameter of the liquid alloy droplet at its tip. The VLS reaction generally leads to the growth of silicon whiskers epitaxially in the <111> direction on single crystal silicon <111> substrates.1-3 Recently, Lieber,4 Lee,5 Yu,6 and coworkers have extrapolated on the ideas entailed in the VLS technique to develop laser ablation of metal containing silicon targets, obtaining bulk quantities of silicon nanowires. More recently, Lee et al.5,7 have shown that oxides play a dominant role in the nucleation and growth of semiconductor nanowires be it by laser ablation, thermal evaporation, or chemical vapor deposition. Lee et al.5 have suggested a new growth mechanism, referred to as oxide assisted nanowire growth, which represents a new approach to nanowire synthesis. Our initial approach8-10 to this problem has involved the application of the techniques of high temperature synthesis to modify the approach of Lee et al. and generate virtually defect free SiO2 sheathed crystalline silicon nanowires and silica (SiO2) nanospheres which can be agglomerated to wire-like configurations impregnated with crystalline silicon nanoclusters. Further controlled condensation can extend this agglomeration to produce nanotubes and nanofiber arrays.