Ultrathin transition metal dichalcogenides (TMDCs) of Mo and W show great potential for digital electronics and novel optoelectronic applications, but the influence of stoichiometry on the electrical and optical properties has been largely overlooked. The stoichiometry of monolayer CVD-grown MoS2 was systematically varied and correlated with the associated changes in optical and electrical properties. Surprisingly, the characteristics of transistor devices were improved by utilizing more defective (less stoichiometric) material.
