Scaling behavior of the quantum Hall plateau-plateau transition in graphene p-n-p junctions

We present the observation of scaling behavior in graphene p-n-p junctions achieved by controlled metallic diffusion. Generally, metal deposition on graphene surface introduces substantial carrier scattering, which undermines the high mobility of intrinsic graphene. However, we discover a weakly functionalized regime of the deposited contact with small carrier scattering, while p-type doping of graphene is realized due to the metal oxide formation. Consequently, the resulted graphene channel are composed of p-type doped and an intrinsic regions. The high-quality graphene p-n-p junctions is evidenced by a pronounced quantum Hall effect and Shubnikov-de Haas oscillations. Remarkably, we observed a well-defined QH plateau-plateau transition of zeroth Landau level, yielding a scaling exponent of {\$}$\backslash $kappa$=$0.21$\backslash $pm0.01{\$}. Moreover, the graphene p-n-p junctions exhibit weak localization behavior, and the coherence length was found to be correlated to carrier scattering in the graphene devices.