Designing the shape evolution of SnSe2 nanosheets and their optoelectronic properties.

Layered chalcogenide materials (LCMs) are emerging materials in recent years for their great potential in applications of electronics and optoelectronics. As a member of LCMs, SnSe2, an n-type semiconductor with a band gap of ∼1.0 eV, is of great value to explore. In this paper, we develop a facile CVD method, for the first time, to synthesize diverse shaped SnSe2 and square SnSe nanosheets (NSs) on SiO2/Si substrates. To the best of our knowledge, the thickness of as-grown SnSe2 is among the thinnest ones synthesized by CVD methods on various substrates. What's more, photodetectors are fabricated to investigate the optoelectronic properties of SnSe2. The on/off ratio of photoswitches reaches 100 under the illumination of an 800 nm laser. This work will pave a new pathway to synthesize LCM nanostructures, shed light on the shape evolution during the growth process and expand the candidates for high performance optoelectronic devices.