Figure 1

(a). AFM images taken on monolayer MoS₂, MoSe₂ and WSe₂. (b). Raman spectrum measured on monolayer MoS₂, MoSe₂ and WSe₂, where the solid and dashed curves correspond to monolayers and few-layers, respectively. (c). Room-temperature normalized PL for monolayer MoS₂, MoSe₂ and WSe₂.