Seed Growth of Tungsten Diselenide Nanotubes from Tungsten Oxides

Abstract

We report growth of tungsten diselenide (WSe 2 ) nanotubes by chemical vapor deposition with a two-zone furnace. WO 3 nanowires were fi rst grown by annealing tungsten thin fi lms under argon ambient. WSe 2 nanotubes were then grown at the tips of WO 3 nanowires through selenization via two steps: (i) formation of tubular WSe 2 structures on the outside of WO 3 nanowires, resulting in core (WO 3 )–shell (WSe 2 ) and (ii) growth of WSe 2 nanotubes at the tips of WO 3 nanowires. The observed seed growth is markedly different from existing substitutional growth of WSe 2 nanotubes, where oxygen atoms are replaced by selenium atoms in WO 3 nanowires to form WSe 2 nanotubes. Another advantage of our growth is that WSe 2 fi lm was grown by simply supplying hydrogen gas, where the native oxides were reduced to thin fi lm instead of forming oxide nanowires. Our fi ndings will contribute to engineer other transition metal dichacogenide growth such as MoS 2 , WS 2 , and MoSe 2 .