Space-confined and substrate-directed synthesis of transition-metal dichalcogenide nanostructures with tunable dimensionality.

Atomically thin transition-metal dichalcogenide (TMDC) nanostructures are predicted to exhibit novel physical properties that make them attractive candidates for the fabrication of electronic and optoelectronic devices. However, TMDCs tend to grow in the form of two-dimensional nanoplates (NPs) rather than one-dimensional nanoribbons (NRs) due to their native layered structure. Herein, we have developed a space-confined and substrate-directed chemical vapor deposition strategy for the controllable synthesis of WS, WSe, MoSe, MoS, WSSe NPs and NRs. TMDC NRs with lengths ranging from several micrometers to 100 μm have been obtained and the widths of TMDC NRs can be effectively tuned. Moreover, we found that TMDC NRs show different growth behaviors on van der Waals (vdW) and non-vdW substrates. The micro-nano structures, optical and electronic properties of synthesized TMDC NRs have been systematically investigated. This approach provides a general strategy for controllable synthesis of TMDC NRs, which makes these materials easily accessible as functional building blocks for novel optoelectronic devices.