Controllable growth of large-area atomically thin ReS_2 films and their thickness-dependent optoelectronic properties

摘要

Rhenium disulfide (ReS2) has drawn much scientific interest as it possesses many distinctive features due to its unusual structure. However, the synthesis of large-area continuous ReS2 films with high crystalline quality is still a challenge to date. Here, chemical vapor deposition (CVD) of the substrate-scale continuous ReS2 film with an atomic thickness and spatial uniformity, as well as its thickness-dependent optoelectronic properties, was reported. By using a space-confined CVD configuration, the ReS2 film on mica with the thickness varying from the monolayer to few layers can be accurately tuned via changing the position of the substrate. HRTEM and AFM images revealed that the grain size of the ReS2 film is on the scale of tens of nanometers. Field effect transistors based on the ReS2 thin film exhibited a high photoresponsivity of 278 mA/W under 405 nm illumination. A decrease in bandgap energy from 1.59 eV in the monolayer to 1.50 eV in bulk and the absorption coefficient as large as 10(5) x cm(-1) in the visible range were found for the ReS2 thin film, suggesting great potential of using ReS2 as an absorber material for photovoltaic application. Published under license by AIP Publishing.