Raman probing of hydrogen-intercalated graphene on Si-face 4H-SiC

We report the results of in-depth Raman study of quasi-free-standing monolayer graphene on the (0001) Si- face of 4H-SiC, which contains similar to 0.1-2.10(11) cm(-2) sp(3) defects that have been introduced by hydrogen intercalation. The nature of the intercalation-induced defects is elucidated and ascribed to the formation of the C-H bonds. At the higher intercalation temperature in the formed monolayer graphene the defect-related Raman scattering displays a great enhancement and new spectral features attributed to D' and D+D' modes appear. Comprehensive statistical analysis of the Raman data enabled us to estimate the homogeneity of the Raman scattering processes and to separate strain and doping effects. Analysis of the compressive strain and carrier density maps revealed that the intercalation temperature of 900 degrees C and intercalation time of 1 h are more favorable conditions for conversion of the buffer layer to uniformly relaxed and p-doped monolayer graphene in comparison to annealing at 1100 degrees C for 30 min.