## 2 Results and Discussion
[51] (Equation (3), A\({}_{\text{D}}\) and A\({}_{\text{G}}\) represent the areas of the D and G band, respectively). \[\text{L}_{\text{D}}^{2}=1.8\cdot 10^{-9}\cdot\lambda_{\text{L}}^{4}\left(\frac{ \text{A}_{\text{D}}}{\text{A}_{\text{G}}}\right)^{-1} \tag{3}\]  
In Figure 4, the A\({}_{\text{D}}\)/A\({}_{\text{G}}\) ratio in C-11 samples annealed at different temperatures was plotted as a function of the L\({}_{\text{D}}\) value. It is clearly shown that A\({}_{\text{D}}\)/A\({}_{\text{G}}\) decreased and L\({}_{\text{D}}\) increased as the annealing temperature of C-11 increased from 1000 to 1800 \({}^{\circ}\)C. In the C-11 sample prepared at 1000 \({}^{\circ}\)C, a L\({}_{\text{D}}\) value of 6 nm was obtained, which means that at least one defect is present within the average lateral size of the crystallite (L\({}_{\text{a}}\) (1000 \({}^{\circ}\)C) = 7.5 nm). By increasing the annealing temperature up to T = 1400 \({}^{\circ}\)C, L\({}_{\text{D}}\) increased giving values in the range of L\({}_{\text{D}}\) = 8-10 nm. This correlated to the appearance end evolution of the D' band in the Raman spectra of the corresponding samples and was similar to the behavior and evolution of nano-graphitic structures. Upon annealing at higher temperatures, the concentration/number of the intrinsic defects was further reduced, giving rise to larger L\({}_{\text{D}}\) and L\({}_{\text{a}}\) values. This is an expected trend, which agreed very well with the description of [PERSON] et al. who identified two stages concerning the evolution of the I\({}_{\text{D}}\)/I\({}_{\text{G}}\) ratio: the first stage corresponded to a high defect concentration situation in the carbon phase and there the I\({}_{\text{D}}\)/I\({}_{\text{G}}\) ratio scales with L\({}_{\text{a}}\) cf. I\({}_{\text{D}}\)/I\({}_{\text{G}}\) = 1/L\({}_{\text{a}}\)\({}^{2}\); whereas the stage two corresponded to a low defect concentration in carbon, with I\({}_{\text{D}}\)/I\({}_{\text{G}}\) = 1/L\({}_{\text{a}}\)[45]. Considering the proposed L\({}_{\text{a}}\) value of ca. 2 nm as a border between the first and second stage and the values obtained for the studied C-11 samples, it could be concluded that  
Figure 3: Plot of the lateral crystal size L\({}_{\text{a}}\) (blue diamonds) as a function of the amount of carbon. Bars represent standard deviation. the carbon phase present in the C-11 samples could be assigned to the second stage, independent of the annealing temperature. Interestingly, not only the trend but also the values of A\({}_{\text{D}}\)/A\({}_{\text{G}}\) ratio and L\({}_{\text{D}}\) were comparable with graphene-based materials in which the disorder was induced and adjusted upon Ar\({}^{+}\) ion bombardment [52] (empty circles in Figure 4). The significant effect of the annealing temperature on the ordering and defect concentration in the sp\({}^{2}\) carbon phase of SiOC/C materials studied in the present work might obviously correlate to their electronic transport. This aspect was addressed by investigating silicon oxycarbide ceramics possessing various amounts of the segregated carbon phase and annealed at different temperatures via dc conductivity and Hall measurements and will be discussed in the following. Figure 5 shows the (logarithmic) room temperature dc conductivity of the SiOC/C samples synthesized at temperatures in the range from 1000 to 1600 \({}^{\circ}\)C as a function of the content of sp\({}^{2}\)-hybridized segregated carbon. It is clearly seen that the dc conductivity shows a dependence on the sp\({}^{2}\) carbon content in SiOC/C, which may be correlated to percolative systems. The critical concentration \(\phi_{\text{crii}}\). (percolation threshold) of sp\({}^{2}\) carbon is shown to depend on the annealing temperature and varied from ca. 20 vol.% for the sample series prepared at 1000 \({}^{\circ}\)C to ca. 6 vol.% for the samples annealed at 1600 \({}^{\circ}\)C (Figure 5).