Ordered selenium nanowire arrays with diameters about 40 nm have been fabricated by electrodeposition using anodic porous alumina templates. As determined by X-ray diffraction, Raman spectra, electron diffraction and high-resolution transmission electron microscopy, selenium nanowires have uniform diameters, which are fully controllable. Single crystalline trigonal selenium nanowires have been obtained after postannealing at 180 degrees C. These nanowires are perfect with a c-axis growth orientation. The optical absorption spectra reveal two types of electron transition activity. (c) 2006 Elsevier Ltd. All rights reserved.