Silver nanowires with an average length of 6 mum and diameter of about 70 nm have been synthesized by polyol reduction of silver nitrate in the presence of polyvinylpyrrolidone. Scanning electron microscopy, transmission electron microscopy and selected area electron diffraction have been employed to elucidate the structure of the Ag nanowires. The results show that the Ag nanowire capped by PVP are truncated decahedron with fivefold symmetry, bounded by {100} planes with [110] growth direction. The monodispersed Ag nanowires can self-assemble into ordered arrays on n-Si(100) wafer due to the strong interaction of PVP on the surface of them. (C) 2003 Elsevier B.V. All rights reserved.