We have observed the energy structure in the density of occupied states of graphene grown on n-type 6H-SiC (0001). The structure revealed with photoelectron spectroscopy is described by creation of the quantum well states whose number and the energy position (E1 = 0.3 eV, E2 = 1.2 eV, E3 = 2.6 eV ) coincide with the calculated ones for deep (V = 2.9 eV) and narrow (d = 2.15 A) quantum well formed by potential relief of the valence bands in the structure graphene/n-SiC. We believe that the quantum well states should be formed also in graphene on dielectric and in suspended graphene.
@article{arxiv.1402.6569,
title = {Size confinement effect in graphene grown on 6H-SiC (0001) substrate},
author = {V. M. Mikoushkin and V. V. Shnitov and A. A. Lebedev and S . P. Lebedev and S. Yu. Nikonov and O. Yu. Vilkov and T. Iakimov and R. Yakimova},
journal= {arXiv preprint arXiv:1402.6569},
year = {2014}
}