# Structural Modifications in Epitaxial Graphene on SiC Following 10 keV Nitrogen Ion Implantation
## 3 Results
### Xps  
Figure 5a shows the C 1s spectra of as grown EG/SiC and implanted EG/SiC at \(1\times 10^{12}\), \(1\times 10^{13}\) and \(1\times 10^{14}\) ions/cm\({}^{2}\) fluences obtained from XPS at takeoff angle of 90\({}^{\circ}\). The C 1s spectra of EG/SiC are characterized by a graphitic carbon (C=C) peak around 284.8 eV and a silicon carbide (Si-C) peak around -283.8 eV. Additionally, due to the graphitization process, a minor contribution around 289.0 eV is due to the formation of O-C=O bonds [48] in the pristine sample. Following N\({}^{+}\) ion implantation, C 1s spectra show a reduction of the intensity of both graphitic carbon (C=C) and silicon carbide peak (Si-C) than the pristine sample. This is indicative of irradiation-induced damages scaling with an increasing fluence, as revealed by the fact that the overall C 1s and Si 2p spectra intensity decreases when going from \(1\times 10^{12}\) to \(1\times 10^{14}\) ions/cm\({}^{2}\).  
Figure 4: Variation in (**a**) relative Raman intensity, (**b**) total disorder following 10 keV N\({}^{+}\) ion implantation.  
Figure 3: **(a)** Raman spectra showing changes in the prominent SiC peaks at varying fluences in N\({}^{+}\) ion-implanted samples; (**b**) Raman spectra of the sample implanted at fluence \(1\times 10^{14}\) ions/cm\({}^{2}\).  
There was a broadening of the C1s spectra in the region between 284.5 eV to 287.5 eV in all ion-implanted samples, Figure 5a It may have been due to the presence of the C=N bond at 285.7 eV following the nitrogen ion implantation in graphene [49]. Figure 5d shows the corresponding N 1s spectra which reveal two components at 397.9 eV and 400.3 eV, that can be assigned to pyridinic and quaternary type N-functionalities, respectively [49,50]. The overall N 1s intensity increased with increasing ion fluence which was indicative of an effective N implantation.  
Figure 5b shows Si 2p spectra with the SiC peak at \(\sim\)101.6 eV in as grown EG/SiC sample in agreement with earlier study [51]. The Si 2p spectra of N\({}^{+}\) ion-implanted samples reveal a decreased intensity of the SiC peak with increasing fluence, in agreement with Raman results (Figure 3). In addition, Si 2p spectra shift towards a lower binding energy approaching BE values which is characteristic of pure Si. [52]. These changes can be interpreted as resulting from breakdown of the Si-C bonds and an increased generation of homonuclear bonds of the sp\({}^{3}\) C-C and Si-Si type (Figure 5b).  
Figure 5c presents the O 1s spectra which clearly depict a fluence dependent rise in the O 1s peak intensity. There appears two peaks at \(\sim\)532.1 and 533.2 eV in the O 1s spectra obtained after deconvolution of the O 1s spectra (data not shown) in the as grown EG/SiC sample, peaks are attributed to C=O and C-OH peak, respectively [53]. The high binding energy component increases by the ion implantation which is indicative of C-OH formation. The XPS showed that dopant concentration can be precisely controlled by controlling the fluence which provides a simple method for developing nitrogenated graphene at varying concentrations and enhances the applicability of EG/SiC in nanoelectronics.