In each measurement, samples were irradiated for 25 sec with a laser of λ = 633 nm with a power of 0.4 mW and a 50 μm pinhole aperture. Five different locations were measured, and five measurements were performed for each location. Data processing implied baseline correction and normalisation of the Raman scattering intensity according to the G band, allowing the quantification of the formation of defects in the graphene lattice through the calculation of the ID/IG ratio.