Figure 5. Normalized Raman spectra raw data using a laser excitation energy of E_L = 2.33 eV, obtained for growth temperatures 800–1100 °C.

The spectra taken from the 1100 °C sample was acquired from the corresponding colored markers shown in Fig. 8a. (a) Raman spectra indicating the high quality graphene growth through PVD. The reduction in D-peak intensity as deposition temperature increases agrees with the I_D/I_G Raman maps and SEM images presented in Fig. 3. The area highlighted in yellow signifies the location of combination Raman modes magnified in (b). The peak shape, intensity, and location of the TS₁ and TS₂ combination Raman modes are indicative of turbostratic stacking.