Structure of bismuth telluride nanowire arrays fabricated by electrodeposition into porous anodic alumina templates

Arrays of bismuth telluride (Bi2Te3) nanowires with diameters of similar to25, similar to50, and similar to75 nm have been produced by electrochemical deposition into porous anodic alumina templates. Scanning electron microscopy confirms that the nanowire arrays are dense with a narrow distribution of nanowire diameters. The structure of the nanowires was assessed immediately after deposition, after annealing to similar to80% of the melting point, and after melting/recrystallization. As determined by XRD analysis, there is strong fiber texture in the arrays that depends on both the nanowire diameter and the postdeposition processing conditions. Bright-field/dark-field imaging and diffraction in the transmission electron microscope reveal that the as-deposited nanowires are polycrystalline with a bamboo-type grain structure that does not change significantly upon annealing, and a similar grain structure is obtained after melting and resolidification.