Synthesis of single crystalline tellurium nanotubes with triangular and hexagonal cross sections.

Single crystalline tellurium (Te) nanotubes with triangular cross sections were successfully synthesized for the first time by a simple approach of vaporizing tellurium metal and condensing the vapor in an inert atmosphere onto a suitable substrate. Tellurium gas was evaporated by heating at 350 degrees C and was condensed on the Si (100) substrate at 150-200 degrees C, in the downstream of argon (Ar) gas at a flow rate of 25 sccm for 10 min. This led to the production of nanotubes of triangular cross section along with some hexagonal ones. The formation of the nanotubes was highly dependent upon the structure of the substrate surface, Ar gas flow rate, and the deposition temperature. When the substrate is Si (111) or sapphire (0001) or when the argon flow rate is increased to 500 sccm, nanowires and nanorods were exclusively formed. Irrespective of the morphologies, all the observed Te nanostructures grew in a regular [0001] direction. The facile approach to nanotubes with a triangular cross section may facilitate some new applications as well as stimulate theoretical studies pertaining to the stability of this high-energy configuration.