Through electroless silver deposition, we have successfully fabricated Si nanowires (SiNWs) in a conventional vessel containing aqueous HF and AgNO3 solution. Their growth mechanisms are analyzed on the basis of a self-assembled localized microscopic electrochemical cell model. A series of scanning electron microscope observations reveal the detailed growth process of the SiNWs. The formation of intermediate Si nanostructures (undetached Si nanotubes) is suggested to be responsible for the growth of triangular shaped SiNWs. The shape and structure of the SiNWs and intermediate undetached Si nanotubes are promising characteristics for applications in interconnection and basic components for future nanoelectronic and optoelectronic devices. (c) 2005 Elsevier B.V. All rights reserved.