Growth of low doped monolayer graphene on SiC(0001) via sublimation at low argon pressure

摘要

Silicon carbide (SiC) sublimation is the most promising option to achieve transfer-free graphene at the wafer-scale. We investigated the initial growth stages from the buffer layer to monolayer graphene on SiC(0001) as a function of annealing temperature at low argon pressure (10 mbar). A buffer layer, fully covering the SiC substrate, forms when the substrate is annealed at 1600 degrees 1C. Graphene formation starts from the step edges of the SiC substrate at higher temperature (1700 degrees C). The spatial homogeneity of the monolayer graphene was observed at 1750 degrees C, as characterized by Raman spectroscopy and magneto-transport. Raman spectroscopy mapping indicated an A(G-graphene)/A(G-HOPG) ratio of around 3.3%, which is very close to the experimental value reported for a graphene monolayer. Transport measurements from room temperature down to 1.7 K indicated slightly p-doped samples (p similar or equal to 10(10) cm(-2)) and confirmed both continuity and thickness of the monolayer graphene film. Successive growth processes have confirmed the reproducibility and homogeneity of these monolayer films.