The effect of the microstructures of Te nanowires on the crystal growth of one-dimensional Bi2Te3 nanotubes

To obtain Bi2Te3 nanotubes with a one-dimensional structure, Te nanowires as a template were prepared by solvothermal synthesis and they were subsequently reacted with Bi, which was formed by a liquid-phase reduction. The alloying between Bi and Te is progressed by the diffusion of atoms on the interface of the two joined metals. Voids formed by migration of Te atoms induce the binary-nanotube of a one-dimensional structure from single-component nanowire. The synthesis temperature of the Te nanowires had a great influence on the alloying into Bi2Te3 nanotubes by changing the microstructure of Te nanowires, including their particle shape and crystal structure. When the reduction rate from Bi3+ ions to Bi metals is constant and the synthesis temperature of Te nanowires is lower or higher than in a range of limited temperature, the diffusion resistance of Te atoms from the inside of the Te nanowire became greater due to the cohesion among the Te nanowires or the increase of crystal density, making it difficult to alloy into Bi2Te3. The microstructures of Te and Bi2Te3, such as particle shape and crystal structure, were investigated using XRD, SEM, TEM, SAED, DSC and XPS.