Atomic layer deposition (ALD) can be used for wafer-scale synthesis of 2D materials.In this paper,a novel,reliable,secure,low-cost,and high-efficiency process for the fabrication of MoS2 is introduced and investigated.The resulting 2D materials show high carrier-mobility as well as excellent electrical uniformity.Using molybdenum pentachloride (MoCl5) and hexamethyldisilathiane (HMDST) as ALD precursors,thickness-controlled MoS2 films are uniformly deposited on a 50 mm sapphire and a 100 mm silica substrate.This is done with a high growth-rate (up to 0.90 A/cycle).Large-scale top-gated FET arrays are fabricated using the films,with a room-temperature mobility of 0.56 cm2/(V·s) and a high on/off current ratio of 106.Excellent electrical uniformity is observed in the whole sapphire wafer.Additionally,logical circuits,including inverters,NAND,AND,NOR,and OR gates,are realized successfully with a high-k HfO2 dielectric layer.Our inverters exhibit a fast response frequency of 50 Hz and a DC-voltage gain of 4 at VDD=4 V.These results indicate that the new method has the potential to synthesize high quality MoS2 films on a large-scale,with hypo-toxicity and enhanced efficiency,which can facilitate a broader range of applications in the future.