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A nonpolar SiC(1120) substrate has been used to fabricate epitaxial graphene (EG). Two EGs with layer numbers of 8-10 (referred to as MLG) and 2-3 (referred to as FLG) were used as representative to study the substrate effect on EG through temperature-dependent Raman scattering. It is found that Raman lineshifts of G and 2D peaks of the MLG with temperature are consistent with that of free graphene, as predicted by theory calculation, indicating that the substrate influence on the MLG is undetectable. While Raman G peak lineshifts of the FLG to that of the free graphene are obvious, however, its lineshift rate ( 0.016 cm-1/K) is almost one third of that ( 0.043cm-1/K) of an EG on 6H-SiC (0001) in the temperature range from 300 K to 400 K, indicating a weak substrate effect from SiC (1120) on the FLG. This renders the FLG with a high mobility around 1812cm2 ·V-1 ·s-1 at room temperature even with a very high carrier concentration about 2.95×1013cm-2 (p-type). These suggest SiC (1120) is more suitable for fabricating EG with high performance.
A nonpolar SiC (1120) substrate has been used to fabricate epitaxial graphene (EG). Two EGs with layer numbers of 8-10 (referred to as MLG) and 2-3 (referred to as FLG) were used as representative to study the substrate effect on EG through temperature-dependent Raman scattering. It is found that Raman lineshifts of G and 2D peaks of the MLG with temperature are consistent with that of free graphene, as predicted by theory calculation, indicating that the substrate influence on the MLG is While RaGG peak lineshifts of the FLG to that of the free graphene are obvious, however, its line shift rate (0.016 cm-1 / K) is almost one third of that (0.043 cm "1 / K) of an EG on 6H-SiC (0001) in the temperature range from 300 K to 400 K, indicating a weak substrate effect from SiC (1120) on the FLG. This renders the FLG with a high mobility around 1812 cm 2 · V-1 · s-1 at room temperature even with a very high carrier concentration about 2.95 × 1013cm-2 (p-type). These suggest SiC (1120) is more suitable for fabricating EG with high performance.