Selective Decoration of Au Nanoparticles on Monolayer MoS2 Single Crystals

Abstract

We report a controllable wet method for effective decoration of 2-dimensional (2D) molybdenum disulfide (MoS₂) layers with Au nanoparticles (NPs). Au NPs can be selectively formed on the edge sites or defective sites of MoS₂ layers. The Au-MoS₂ 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 MoS₂ layers. Field effect transistors were directly fabricated by placing ion gel gate dielectrics on Au-decorated MoS₂ layers without the need to transfer these MoS₂ layers to SiO₂/Si substrates for bottom gate devices. The ion gel method allows probing the intrinsic electrical properties of the as-grown and Au-decorated MoS₂ layers. This study shows that Au NPs impose remarkable p-doping effects to the MoS₂ transistors without degrading their electrical characteristics.