Formation of single-crystal tellurium nanowires and nanotubes via hydrothermal recrystallization and their gas sensing properties at room temperature

Single-crystal tellurium nanowires and nanotubes were selectively synthesized from tellurium powder through a hydrothermal recrystallization route. The nanowires have an average diameter of 40 nm and lengths of several micrometers, while the nanotubes have diameters of 100-200 nm and lengths of 1-2 mm. The morphologies of the as-obtained tellurium nanocrystals could be controlled by tuning the amount of hydrochloric acid added in the hydrazine hydrate solution. The experimental results demonstrated that tellurium powder could be dissolved and recrystallized in hydrazine hydrate solution under hydrothermal conditions. A dissolution-recrystallization mechanism was proposed for the conversion from tellurium powder to tellurium nanowires or nanotubes. The gas sensing properties of as-synthesized tellurium nanowires and nanotubes were investigated in detail, which revealed that the as-prepared tellurium nanowires and nanotubes, especially the tellurium nanowires, exhibited excellent sensitivity to NH(3) at room temperature. The response times of the tellurium nanowires and nanotubes were 5 s and 18 s, and the recovery times were 720 s and 170 s, respectively, which are shorter than those reported for tellurium films. The as-prepared tellurium nanostructures could have potential applications in nanosensors.