Controlled growth of atomically thin MoSe2 films and nanoribbons by chemical vapor deposition

Atomically thin transition metal dichalcogenides (TMDCs) have drawn much interest for their promising applications in electronic, optoelectronic, valleytronic and sensing fields. Controlled growth of large-scale and high-quality TMDC nanostructures is highly desirable but remains challenging. In the present work, large-scale monolayer, bilayer and few-layer MoSe2 films have been controllably synthesized by ambient pressure chemical vapor deposition (APCVD). Hydrogen flow rate, growth temperature as well as selenium-metal flux ratio have been systematically investigated, which were demonstrated to play a key role in the synthesis of MoSe2 nanostructures. We have also reported the successful growth of MoSe2 nanoribbons with controlled width and length on diverse substrates by APCVD with the assistance of sodium chloride and corresponding growth mechanism was proposed. Our findings highlight the prospects for the controlled growth of novel 1D and 2D TMDC nanostructures for nanoelectronic devices and the development of mixed-dimensional heterostructures.