Size confinement effect in graphene grown on 6H-SiC (0001) substrate
  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. 
V.M. Mikoushkin, V.V. Shnitov, A.A. Lebedev, S .P. Lebedev, S.Yu.   Nikonov, O.Yu. Vilkov, T. Iakimov, R. Yakimova
cond-mat.mtrl-sci