▎ 摘　　要

We present an experimental investigation of the impact of size effects on conductance in nanoribbons fabricated from epitaxial graphene. The material resistivity is seen to increase significantly (up to 13 x for 50 nin wide ribbons) upon conversion from bulk graphene to nanoribbons. As the ribbon width is scaled below 100 nm, the resistivity is seen to be increasingly affected by substrate morphology. Size effects set in earlier for low-quality samples, and the resistivity shows a weaker dependence on width; this is attributed to increased boundary scattering weakening the width dependence of resistivity. The opposite behavior is witnessed for high-quality samples. On moderate-quality samples, 20 nm graphene nanoribbons show a 6 x degradation of mobility compared to as-grown values.