Amorphous silicon nanowire films were rationally synthesized using a simple approach. The films consist of highly oriented nanowires of 30 mum in length and 20-80 nm in diameter. The morphology, microstructure features, and chemical composition of the nanowires were analyzed using electron microscopy and Raman spectroscopy. A novel model concerning solid-liquid-solid phases was proposed to explain the growth mechanism of the nanowires. This approach should be very useful to direct the controlled growth of nanomaterials. (C) 2003 Published by Elsevier Science B.V.