Probing the electrical anisotropy of multilayer graphene on the Si face of 6H-SiC

We studied the in-plane magnetoresistance R(B, T) anisotropy in epitaxial multilayer graphene films grown on the Si face of a 6H-SiC substrate that originates from steplike morphology of the SiC substrate. To enhance the anisotropy, a combination of argon atmosphere with graphite capping was used during the film growth. The obtained micro-Raman spectra demonstrated a complex multilayer graphene structure with the smaller film thickness on terraces as compared to the step edges. Several Hall bars with different current/steps mutual orientations have been measured. A clear anisotropy in the magnetoresistance has been observed, and attributed to variations in electron mobility governed by the steplike structure. Our data also revealed that (i) the graphene-layer stacking is mostly Bernal type, (ii) the carriers are massive, and (iii) the carriers are confined to the first 2-4 graphene layers following the buffer layer.