Similarly, several reflectivity peaks are formed (Fig. ) in both VR and UV regions, with very low intensity, for the strain-free monolayer. The maximum reflectivity is only 0.078 (at 7.33 eV) which is lower to that value of PG (0.12) . Reflection spectra shows blue-shift (red-shift) with the growth in amplitude up to 0.096 (at 4% ) by compressive (tensile) strain. Interestingly, the minor reflectivity peaks show that this monolayer becomes transparent in the energy range above 15 eV.