Figure 3.

Micro-Raman investigation of the monodomain WSe₂. (a) Optical microscope image of a typical monolayer WSe₂ with bilayer domain on the center. (b) The Raman spectra of the monolayer and bilayer WSe₂. (c) and (d) Typical Raman map of the single domain monolayer (c, center wavenumber: ∼ 252 cm^–1) with bilayer (d, center wavenumber: ∼ 307 cm^–1) WSe₂ domain. (e) Optical microscope image of large scale monolayer WSe₂ with several bilayer or few-layer domain. (f) Raman map of the large scale monolayer (center wavenumber: ∼ 250 cm^–1) WSe₂ with several bilayer and few-layer domain. Scale bars of panels a, c, and d are all 5 μm; Scale bars of panels e and f are 10 μm.