Transport properties of bismuth nano-wire systems.
Abstract
Ultra-fine Bi nano-wires (10--120 nm diameter) with packing density as high as 7×10^10/cm^2 were fabricated by pressure injecting molten Bi into the evacuated channels of an anodic alumina template. The resulting Bi nano-wires are shown to be single crystals (with the same structure as bulk Bi) and all the nano-wires are similarly oriented. The small effective mass of Bi, high anisotropy of its Fermi surface, and the high aspect ratio (length/diameter) of Bi nano-wires make this an excellent system for studying quantum confinement effects in a one-dimensional (1D) electron gas. Transport properties, such as electrical conductivity, magnetoresistance and thermoelectric power, are investigated for both Bi nano-wire arrays and free-standing Bi nano-wires with various wire diameters (10-120 nm) and Te doping concentrations (0.025-0.5 at.%), and at various temperatures and magnetic fields. A theoretical model based on the basic band structure of bulk Bi, suitably modified for the 1D situation, explains the many unusual effects that are observed. Strong evidence is provided for an interesting quantum confinement-induced semimetal to semiconductor transition in such Bi nano-wires.
- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- March 1998
- Bibcode:
- 1998APS..MAR.G3204Z