Sub-millimeter size high mobility single crystal MoSe2 monolayers synthesized by NaCl-assisted chemical vapor deposition

Abstract

Monolayer MoSe2 is a transition metal dichalcogenide with a narrow bandgap, high optical absorbance andlarge spin-splitting energy, giving it great promise for applications in thefield of optoelectronics. Producingmonolayer MoSe2films in a reliable and scalable manner is still a challenging task as conventional chemicalvapor deposition (CVD) or exfoliation based techniques are limited due to the small domains/nanosheetsizes obtained. Here, based on NaCl assisted CVD, we demonstrate the simple and stable synthesis ofsub-millimeter size single-crystal MoSe2monolayers with mobilities ranging from 38 to 8 cm2V 1s 1.The average mobility is 12 cm2V 1s 1. We further determine that the optical responsivity of monolayerMoSe2is 42 mA W 1, with an external quantum efficiency of 8.22%.