Effect of surface morphology on the electron mobility of epitaxial graphene grown on 0° and 8° Si-terminated 4H-SiC substrates

Abstract

Graphene with different surface morphologies were fabricated on 8°-off-axis and on-axis 4H-SiC(0001) substrates by high-temperature thermal decompositions. Graphene grown on Si-terminated 8°-off-axis 4H-SiC(0001) shows lower Hall mobility than the counterpart of on-axis SiC substrates. The terrace width is not responsible for the different electron mobility of graphene grown on different substrates, as the terrace width is much larger than the mean free path of the electrons. The electron mobility of graphene remains unchanged with an increasing terrace width on Si-terminated on-axis SiC. Interface scattering and short-range scattering are the main factors affecting the mobility of epitaxial graphene. After the optimization of the growth process, the Hall mobility of the graphene reaches 1770 cm2/V·s at a carrier density of 9.8. × 1012 cm−2. Wafer-size graphene was successfully achieved with an excellent double-layer thickness uniformity of 89.7% on a 3-inch SiC substrate.