Fig. 1. Schematic illustration for the experimental set-up

Fig. 2. Optical micrographs of the WSe₂ grown at the positions with different pulling distances

Fig. 3. Optical micrographs of the WSe₂ pulled at different time points during the growth

Fig. 4. Optical microscopic images and fluorescence images of WSe₂

Fig. 5. Optical microscopic image, fluorescence image and fluorescence intensity map of WSe₂

Fig. 6. Raman spectrum of a monolayer WSe₂

Fig. 7. Monolayer WSe₂ AFM topography and the height profile along the red path