Controlled CVD growth of Cu–Sb alloy nanostructures

Abstract

Sb based alloy nanostructures have attracted much attention due to their many promisingapplications, e.g. as battery electrodes, thermoelectric materials and magneticsemiconductors. In many cases, these applications require controlled growth of Sb basedalloys with desired sizes and shapes to achieve enhanced performance. Here, we report aflexible catalyst-free chemical vapor deposition (CVD) process to prepare Cu–Sbnanostructures with tunable shapes (e.g. nanowires and nanoparticles) by transporting Sbvapor to react with copper foils, which also serve as the substrate. By simply controllingthe substrate temperature and distance, various Sb–Cu alloy nanostructures, e.g. Cu11Sb3 nanowires(NWs), Cu2Sb nanoparticles (NPs), or pure Sb nanoplates, were obtained. We also found that the growth ofCu11Sb3 NWs in such a catalyst-free CVD process was dependent on the substratesurface roughness. For example, smooth Cu foils could not lead to the growth ofCu11Sb3 nanowires while roughening these smooth Cu foils with rough sand papers could result in the growthof Cu11Sb3 nanowires. The effects of gas flow rate on the size and morphology of the Cu–Sb alloynanostructures were also investigated. Such a flexible growth strategy could be of practicalinterest as the growth of some Sb based alloy nanostructures by CVD may not be easy dueto the large difference between the condensation temperature of Sb and the other element,e.g. Cu or Co.