High mobility and high on/off ratio field-effect transistors based on chemical vapor deposited single-crystal MoS2 grains

We report the electrical characteristics of field-effect transistors (FETs) with single-crystal molybdenum disulfide (MoS2) channels synthesized by chemical vapor deposition (CVD). For a bilayer MoS2 FET, the field-effect mobility is ∼17 cm2 V−1 s−1 and the on/off current ratio is ∼108, which are much higher than those of FETs based on CVD polycrystalline MoS2 films. By avoiding the detrimental effects of the grain boundaries and the contamination introduced by the transfer process, the quality of the CVD MoS2 atomic layers deposited directly on SiO2 is comparable to or better than the exfoliated MoS2 flakes. The result shows that CVD is a viable method to synthesize high quality MoS2 atomic layers.