Enhanced dielectric deposition on single-layer MoS with low damage using remote N plasma treatment.

Using remote N plasma treatment to promote dielectric deposition on the dangling-bond free MoS is explored for the first time. The N plasma induced damages are systematically studied by the defect-sensitive acoustic-phonon Raman of single-layer MoS, with samples undergoing O plasma treatment as a comparison. O plasma treatment causes defects in MoS mainly by oxidizing MoS along the already defective sites (most likely the flake edges), which results in the layer oxidation of MoS. In contrast, N plasma causes defects in MoS mainly by straining and mechanically distorting the MoS layers first. Owing to the relatively strong MoS-substrate interaction and chemical inertness of MoS in N plasma, single-layer MoS shows great stability in N plasma and only stable point defects are introduced after long-duration N plasma exposure. Considering the enormous vulnerability of single-layer MoS in O plasma and the excellent stability of single-layer MoS in N plasma, the remote N plasma treatment shows great advantage as surface functionalization to promote dielectric deposition on single-layer MoS.