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.