Gold nanoparticle assisted synthesis of MoS 2 monolayers by chemical vapor deposition.

The use of metal nanoparticles is an established paradigm for the synthesis of semiconducting one-dimensional nanostructures. In this work we study their effect on the synthesis of two-dimensional semiconducting materials, by using gold nanoparticles for chemical vapor deposition growth of two-dimensional molybdenum disulfide (MoS 2 ). In comparison with the standard method, the employment of gold nanoparticles allows us to obtain large monolayer MoS 2 flakes, up to 20 μm in lateral size, even if they are affected by the localized overgrowth of MoS 2 bilayer and trilayer islands. Important modifications of the optical and electronic properties of MoS 2 triangular domains are reported, where the photoluminescence intensity of the A exciton is strongly quenched and a shift to a positive threshold voltage in back-gated field effect transistors is observed. These results indicate that the use of gold nanoparticles influences the flake growth and properties, indicating a method for possible localized synthesis of two-dimensional materials, improving the lateral size of monolayers and modifying their properties.