We have achieved mobilities in excess of 200,000 cm^2/Vs at electron densities of ~2*10^11 cm^-2 by suspending single layer graphene. Suspension ~150 nm above a Si/SiO_2 gate electrode and electrical contacts to the graphene was achieved by a combination of electron beam lithography and etching. The specimens were cleaned in situ by employing current-induced heating, directly resulting in a significant improvement of electrical transport. Concomitant with large mobility enhancement, the widths of the characteristic Dirac peaks are reduced by a factor of 10 compared to traditional, non-suspended devices. This advance should allow for accessing the intrinsic transport properties of graphene.
@article{arxiv.0802.2389,
title = {Ultrahigh electron mobility in suspended graphene},
author = {K. I. Bolotin and K. J. Sikes and Z. Jiang and M. Klima and G. Fudenberg and J. Hone and P. Kim and H. L. Stormer},
journal= {arXiv preprint arXiv:0802.2389},
year = {2009}
}