The electrical potential on the surface of ∼300 nm thick SiO2 grown on single crystalline Si substrates has been characterized at ambient conditions using electric field microscopy. Our results show an inhomogeneous potential distribution with fluctuations up to ∼0.4V within regions of 1μm. The potential fluctuations observed at the surface of these usual dielectric holders of graphene sheets should induce strong variations in the graphene charge densities and provide a simple explanation for some of the anomalous behaviors of the transport properties of graphene.
@article{arxiv.0905.2941,
title = {Disordered Electrical Potential Observed on the Surface of SiO$_2$ by Electric Field Microscopy},
author = {N. García and Zang Yan and A. Ballestar and J. Barzola-Quiquia and F. Bern and P. Esquinazi},
journal= {arXiv preprint arXiv:0905.2941},
year = {2015}
}