Synthesis and ambipolar transistor properties of tungsten diselenide nanotubes

Recently, the electrical properties of inorganic nanotubes made by rolling up transition metal dichalcogenide sheets have attracted much attention. There are various types of inorganic nanotubes with different metal and chalcogen atoms, which can provide a variety of electrical properties; however, the inorganic nanotubes whose electrical properties were revealed have been mostly limited to WS2 nanotubes. Here, we investigated the electrical properties of another type of inorganic nanotube, namely, WSe2 nanotubes, and revealed their ambipolar transistor properties through the development of a facile synthesis method. WSe2 nanotubes were synthesized by the selenization of solution-synthesized tungsten oxide nanowires. We found that the introduction of a specific concentration of H2 during selenization was crucial for obtaining WSe2 nanotubes with relatively small diameters. The obtained WSe2 nanotubes exhibited ambipolar transistor operation with higher performance than WS2 nanotubes.