A new routine to fabricate Bi single crystalline tapering junction nanowire arrays

Large-scale tapering junction Bi nanowire arrays have been synthesized by pulsed electrodeposition within a porous anodic alumina membrane (AAM). Bi metal–semiconductor and semiconductor–semiconductor junction nanowires with different diameters were fabricated easily by modulating only the pulse time using only an ordinary AAM template. The morphology and structure of the tapering junction Bi nanowire arrays and individual nanowires are characterized by scanning electron microscopy and transmission electron microscopy. The voltage–current measurements show the intrinsic nonlinear and asymmetric characteristics of metal–semiconductor junction nanowires. PACS 81.05.Bx; 82.80.Fk; 73.63.Nm