▎ 摘 要
We performed a temperature dependent study of the charge and spin transport properties of epitaxial graphene on the C-terminated (000 (1) over bar) face of silicon carbide (SiC), a system without a carbon buffer layer between the graphene and the SiC. Using spin Hanle precession in the nonlocal geometry, we measured a spin relaxation length of lambda(S) = 0.7 lm at room temperature, lower than in exfoliated graphene. We show that the charge and spin diffusion coefficient, D-C and D-S, respectively, increasingly deviate from each other during electrical measurements up to a difference of a factor 4. Thus, we show that a model of localized states that was previously used to explain D-C not equal D-S, can also be applied to epitaxial graphene systems without a carbon buffer layer. We attribute the effect to charge trap states in the interface between the graphene and the SiC. Published by AIP Publishing.