Successive Solution-Liquid-Solid (SLS) Growth of Heterogeneous Nanowires

We report herein that heterogeneous nanowires (NWs) can grow from a catalyst via the successive solution-liquid-solid (SLS) mechanism. First, highly crystalline PbSe NWs were successfully synthesized using Bi catalysts via the SLS mechanism. TOPS solution was added into the solution bearing PbSe NWs. S atoms from TOPS and the excess Pb atoms remaining in the solution penetrated into the liquid Bi catalysts attached to the tips of PbSe NWs. The Pb and S atoms induced the local supersaturation in the outer parts of liquid Bi catalysts due to the limited solubility, leading to the second SLS growth of PbS NWs. The PbS NWs grew along the one side or two sides of PbSe NWs as they epitaxially well match to each other. A possible growth mechanism related to the above phenomena was proposed based upon the surface diffusion model of the vapor-liquid-solid (VLS) process and the geminate NW nucleation mechanism. This is the first report demonstrating that two or three heterogeneous NWs can grow from the same catalyst through the successive SLS growth, and we believe that our results will contribute to the better understanding of the SLS mechanism.