The atomic structure of the heterostructure is provided in Figure . The optimized lattice parameter for this heterostructure is found to be a=b=9.78 Å (see Figure , supporting information). The measured C-C and W-S bond distances 1.42 and 2.45 Å, respectively, which is the same as in the case of their isolated layers. Further, we also optimized the equilibrium interlayer distance (IL D ) between the graphene and WS 2 as shown in Figure (refer supporting information) by including DFT-D3 correction and the optimum value has been found to be = 3.43 Å, which is quite similar to the many of the existing 2D materials. An important parameter that determines the stability of any vdW heterostructure is the binding energy/atom (E b ). The E b is calculated as,