Transition metal dichalcogenides (TMDCs) are promising two-dimensional (2D) materials for next-generation optoelectronic devices; they can also provide opportunities for further advances in physics. Structuring 2D TMDC sheets as nanoribbons has tremendous potential for electronic state modification. However, a bottom-up synthesis of long TMDC nanoribbons with high monolayer selectivity on a large scale has not yet been reported yet. In this study, we successfully synthesized long WxOy nanowires and grew monolayer WS2 nanoribbons on their surface. The supply of source atoms from a vapor-solid bilayer and chemical reaction at the atomic-scale interface promoted a self-limiting growth process. The developed method exhibited a high monolayer selection yield on a large scale and enabled the growth of long (∼100 μm) WS2 nanoribbons with electronic properties characterized by optical spectroscopy and electrical transport measurements. The produced nanoribbons were isolated from WxOy nanowires by mechanical exfoliation and used as channels for field-effect transistors. The findings of this study can be used in future optoelectronic device applications and advanced physics research.
Keywords: chemical vapor deposition; field-effect transistor; nanoribbons; photoluminescence; self-limiting growth; transition metal dichalcogenide.