# Electronic and Transport Properties of Epitaxial Graphene on SiC and 3C-SiC/Si: A Review
## 4 Electronic and Transport Properties: Effect of Interactions with the Surroundings
### Temperature-Dependent Transport: Scattering Mechanisms  
Temperature-dependent Hall effect measurements in EG/SiC and 3C-SiC are crucial to investigate the charge transport as it provides information on the scattering mechanisms. This section summarizes the temperature-dependent transport properties of EG on Si-face SiC, EG on C-face SiC, and EG on 3C-SiC. In general, [PERSON] et al. [93] reported that the carrier scattering mechanism dominant in MLG (on SiO\({}_{2}\)) is Coulomb scattering by randomly charged impurities at the graphene-substrate interface, as also reported by [PERSON] et al. [127]. The same group determined the typical random charged impurity concentration to be \(\sim\)10\({}^{12}\) cm\({}^{2}\) and suggested that, by reducing this impurity concentration to \(\sim\)10\({}^{10}\) cm\({}^{2}\) range, it should lead to a significant increase in the EG mobility. The charge transport in graphene dominated by the charged impurities in the substrate can be theoretically described by the Drude-Boltzmann model [93], which is valid only in the high-density regime [128]. The Fermi temperature of graphene is about 1300 K for n\(\sim\)10\({}^{12}\) cm\({}^{2}\), which indicates no temperature dependence of the MLG conductivity arising from charged impurity scattering within a 0-300 K temperature range in agreement with the experimental observation of graphene flakes [93]. In contrast to the graphene flake results, MLG on Si-face SiC shows a strong temperature dependence of mobility and resistivity, as shown in Figure 14[83, 123, 129]. At carrier concentrations away from the charge neutrality point (above 10\({}^{11}\) cm\({}^{-2}\)), the mobility decreases with increasing the temperature and the resistivity increases [123]. A remote phonon scattering originating from the SiC substrate including the buffer layer and the C-Si bonds at the interface was reported as the reason for the strong temperature dependence of mobility and resistivity, and the limitation of both properties at high temperatures [26, 123, 130, 131]. [PERSON] et al. [56] reported that the suppression of conductivity in high temperatures in the case of monolayer or bilayer Si-face EG is due to the scattering from the point defects present in the interfacial layer. Figure 14: (**a**) Temperature dependent mobility of MLG on SiC (0001). Reprinted with permission from Reference [26]. Copyright (2009) Springer Nature. (**b**) Temperature dependent resistivity of MLG on SiC (0001). Reprinted with permission from Reference [123]. Figure 13: Mobility and sheet carrier density for EG on 3C-SiC/Si combined with those of monolayer EG on the Si-face of 4H-SiC and 6H-SiC substrates at 300 and 77 K from [PERSON] et al. [36]. Reprinted with permission from Reference [21]. Copyright (2020) American Chemical Society. Figure 15 indicates the sheet resistance of rotationally disordered MEG (\(\sim\)10 layers) formed on SiC(0001) [132], which indicates that the sheet resistance remains nearly stable within 0-300 K. This has been related to the weak substrate interaction of EG on the C-face SiC [11]. The mobility, in this case, does not significantly depend on temperature [8]. The phonon scattering is suppressed, and the scattering from impurities is weak. Figure 16 shows mobility versus temperature for EG/3C-SiC substrates [21]. The mobility of EG/3C-SiC (100) shows only a weak temperature dependence, slowly increasing after 200 K and reaching a value of \(\sim\)30 cm\({}^{2}\cdot\)V\({}^{-1}\cdot\)s\({}^{-1}\) at 300 K. This indicates charge impurity scattering. The weak temperature dependence of the mobility of EG/3C-SiC(100) is consistent with Reference [83] for EG on SiC, and is attributed to the absence of the buffer layer.