One-step Electrochemical Synthesis of gas-solid Transformation, Surfactant-free Tellurium Nanowires, Optical Properties and Applications
Tasi Hung Wei1*, Wang Yi Chung1, Yen Yu Ting1, Chen Chia Wei1
1material science and engineering, National Tsing Hua University, Hsinchu, Taiwan
* presenting author:Hung-Wei Tsai,
One-dimensional (1D) nanostructured materials with high surface area to volume ratio, such like nanowires, nanobelts, and nanotubes, reveal different physical and chemical properties from bulk materials and have been demonstrated in various applications including field emission, lasers, interconnection in electronics, photovoltaics, resistive random-access memory (RRAM), and kinds of sensors.
Elemental tellurium is a narrow bandgap semiconductor with a direct bandgap energy of 0.33 eV, and the spiral chains of bonded atoms in its crystal structure result in the highly anisotropic growth tendency. Crystalline tellurium nanowires exhibit extraordinary electrical, fluorescent, piezoelectrical properties and show potential applications in field emitters, supercapacitor, image labels, piezoelectric energy harvesters. Here, we propose a gas-solid transformation mechanism to synthesize surfactant-free tellurium nanowires with average diameter under 20 nm at room temperature by one-step electrochemical method. The tellurium nanowires grow along the [001] direction due to the unique spiral chains in crystal structure and show an enhanced Raman scattering effect, a broad absorption band over the range of 400-700 nm and an emission band over the range of 450-630 nm in photoluminescence spectrum. Besides, the tellurium nanowires are directly applied as p-type dopant to dope graphene and cause a right shift of Dirac point in graphene field-effect transistor. Finally, we utilize the tellurium nanowires as a supercapacitor electrode and a specific capacitance of 24 Fg-1.

Keywords: tellurium, nanowire, supercapacitor, graphene field effect transistor