On the study of silicon nano-wires self-assembled as particles

Two different types of Silicon nano-wires (SiNWs) have been observed by sca nning and transmission electron microscopy. One are of free standing SiNWs deposited uniformly on the surface of silicon substrates, and the other are self-assembled into special shaped particles. These SiNWs were synthesized by thermal evaporation of SiO amorphous powders without any metal catalyst s in the temperature range of 900-1250 degreesC. Growth history reveals tha t the self-assembled SiNWs are formed by original nucleation from the surfa ce of amorphous SiOx particle matrices through phase separation and silicon precipitation followed by further growth through oxide-assisted vapor-soli d reactions. The above results provide a solid experimental support for the oxide-assisted growth model of SiNWs.