Selective Decoration of Au Nanoparticles on Monolayer MoS(2) Single Crystals

We report a controllable wet method for effective decoration of 2-dimensional (2D) molybdenum disulfide (MoS(2)) layers with Au nanoparticles (NPs). Au NPs can be selectively formed on the edge sites or defective sites of MoS(2) layers. The Au-MoS(2) nano-composites are formed by non-covalent bond. The size distribution, morphology and density of the metal nanoparticles can be tuned by changing the defect density in MoS(2) layers. Field effect transistors were directly fabricated by placing ion gel gate dielectrics on Au-decorated MoS(2) layers without the need to transfer these MoS(2) layers to SiO(2)/Si substrates for bottom gate devices. The ion gel method allows probing the intrinsic electrical properties of the as-grown and Au-decorated MoS(2) layers. This study shows that Au NPs impose remarkable p-doping effects to the MoS(2) transistors without degrading their electrical characteristics.