A Solution-Based Approach to Semiconductor Nanowires

The solution phase synthesis of narrow diameter (< 10 nm) straight and branched CdSe and PbSe nanowires (NWs) is described. Crystalline NWs with lengths up to 10 microns are grown in solution, where NW growth is initiated by Au/Bi core/shell nanoparticles (NPs). These NPs have diameters less than 5 nm and are catalytically active towards the growth of similar diameter NWs. Such wires may exhibit quantum confinement effects since the exciton Bohr radius of CdSe (PbSe) is 5.6 (46) nm. Branched NWs are also obtained by varying the reaction conditions, yielding tripod, v-shaped, and y-shaped NWs in the case of CdSe and right angle and t-shape NWs in the case of PbSe. The morphologies obtained in each case emphasize the influence of crystal phase on NW growth. A geminate nucleation mechanism is described to explain NW branching.