Synthesis of sub-20-nm-sized bismuth 1-D structures using gallium-bismuth systems

Bismuth (Bi) nanowires are interesting one-dimensional systems due to the significant quantum confinement effects exhibited as a function of the wire diameters, and synthesizing Bi nanowires with sizes below 20 nm is of fundamental importance in understanding quantum effects. Here, we report a bulk synthesis method to synthesize ultrafine Bi nanowires and a new morphology of bismuth nanostructures, tapered whiskers. These tapered whiskers are about 10-20 mum in length and have diameters of 5-10 nm at the tip and 250-500 nm at the base. The synthesis method is based upon the multiple nucleation and basal growth of nanometer scale nuclei from molten gallium (Ga) melts that result from the low solubility of Bi in Ga and the low eutectic temperature of the Ga-Bi binary system. Adopting different methods of supplying bismuth and using variations in simple heating and cooling, we have synthesized a variety of bismuth nanostructures.