We report on transport characteristics of quantum dot devices etched entirely in graphene. At large sizes, they behave as conventional single-electron transistors, exhibiting periodic Coulomb blockade peaks. For quantum dots smaller than 100 nm, the peaks become strongly non-periodic indicating a major contribution of quantum confinement. Random peak spacing and its statistics are well described by the theory of chaotic neutrino (Dirac) billiards. Short constrictions of only a few nm in width remain conductive and reveal a confinement gap of up to 0.5eV, which demonstrates the in-principle possibility of molecular-scale electronics based on graphene.
@article{arxiv.0801.0160,
title = {Chaotic Dirac billiard in graphene quantum dots},
author = {L. A. Ponomarenko and F. Schedin and M. I. Katsnelson and R. Yang and E. H. Hill and K. S. Novoselov and A. K. Geim},
journal= {arXiv preprint arXiv:0801.0160},
year = {2008}
}