## 3 Results and Discussion
In turn, the ratio of I\({}_{\rm D}\) to I\({}_{\rm G}\) (I\({}_{\rm D}\)/I\({}_{\rm G}\)) reflects the quality of the graphene (Figure 3e,h) [46]. Figure 3d-i shows the maps for the intensity ratio of 2D and G (I2D/I\({}_{\rm G}\)), the intensity ratio of D and G (I\({}_{\rm D}\)/I\({}_{\rm G}\)) Raman bands and maps of 2D peak FWHM. From these maps we can identify areas with different values of the ratios I2D/I\({}_{\rm G}\) and I\({}_{\rm D}\)/I\({}_{\rm G}\). The value of the I2D/I\({}_{\rm G}\) ratio greater than 1.3 apparently belongs to the areas of a single-layer graphene with characteristic values of FWHM 2D bands \(\sim\)30 cm\({}^{-1}\)[46; 50; 51; 52; 53; 54; 55]. In addition, these sections of graphene have a slight value of I\({}_{\rm D}\)/I\({}_{\rm G}\) (\(\sim\)0.175) (Figure S3c), which also corresponds to single-layer graphene with a small number of defects [46]. Besides the regions typical of SLG, there are areas of FLG graphene with a lower I2D/I\({}_{\rm G}\) ratio. For such regions the value of the I2D/I\({}_{\rm G}\) ratio is mainly from 0.5 to 1.25 (Figure 3d and Figure S3a). The value of the FWHM 2D-range is between 44 and 68 cm\({}^{-1}\). This indicates the presence of regions of few-layer graphene. It is noteworthy that for regions of FLG, the values of the I\({}_{\rm D}\)/I\({}_{\rm G}\) (\(\sim\)0.11) (Figure S3d) ratio are less than that for SLG (Figure S3c). In particular, an increase in the I\({}_{\rm D}\)/I\({}_{\rm G}\) ratio suggests that much higher defects prevail and are easily induced in thinner layers [55]. A comparative analysis of histograms of the I2D/I\({}_{\rm G}\) intensity ratios and I\({}_{\rm D}\)/I\({}_{\rm G}\) for an area of 70 \(\times\) 70 \(\upmu\)m (Figure S3) indicates the predominance of single-layer over two-layer fractions in the resulting graphene, which is also confirmed by spectrophotometry data (see Figure 3a). The average values of the FWHM 2D bands for SLG and FLG are about 41 and 56 cm\({}^{-1}\), respectively (Figure S3e,f). In turn, a sample of a multilayer graphene is characterized by a significant decrease in the ratio of I2D/I\({}_{\rm G}\) (Figure 3g) and an increase in the ratio of I\({}_{\rm D}\)/I\({}_{\rm G}\) (Figure 3h). The value of the FWHM 2D bands are significantly increased (Figure 3i). A comparative analysis of the histograms (Figure S3) demonstrates the average value of the ratio I2D/I\({}_{\rm G}\) is \(\sim\)0.08 and \(\sim\)0.61 for I\({}_{\rm D}\)/I\({}_{\rm G}\), while the average value of the FWHM 2D bands is \(\sim\)111 cm\({}^{-1}\) (Figure S3b,g,h). These results indicate the similarity of the synthesized multilayer graphene with graphitized carbon [56]. Various types of defects play an important role in the process of the nucleation and growth of III-nitrides on the graphene surface [21; 57]. The studied samples differed in the values of the RMS (Figure 2b,e,h) and the density of defects (Figure 3e,h). A Raman analysis confirmed this conclusion (we adopted the I\({}_{\rm D}\)/I\({}_{\rm G}\) ratio as a measure of the density of point defects in graphene [58; 59; 60; 61; 62; 63; 64]). The defect density (\(n_{D}\)) in the graphene samples used was quantified from the I\({}_{\rm D}\)/I\({}_{\rm G}\) ratio as \(n_{D(SLG)}\)\(\sim\)3.93 \(\times\) 10\({}^{10}\) cm\({}^{-2}\), \(n_{D(FLG)}\) = 2.47 \(\times\) 10\({}^{10}\) cm\({}^{-2}\) and \(n_{D(MLG)}\) = 1.37 \(\times\) 10\({}^{11}\) cm\({}^{-2}\) for SLG, FLG and MLG, respectively. The topic of distinguishing between the Raman spectra of one and another type of defective _sp\({}^{2}\)_ carbon remains an area for future study. Thus, for further studies of the epitaxy of nitrides, we obtained two separate graphene samples transferred to the amorphous surface of SiO\({}_{2}\)/Si substrates. Based on the resultsof Raman spectroscopy and light transmission (Figure 3) of the obtained graphene samples, it is possible to identify SLG, FLG and MLG regions.