▎ 摘　　要

We use secondary electron spectroscopy to probe the excited states of graphene adsorbed on a Ni(111) surface. A fine structure directly related to the empty bands above the vacuum level of the sample is resolved in the spectra excited by electrons. Ion-induced spectra reveal a high energy feature that is consistent with electron promotion from valence to conduction band states, from which electrons emerge into vacuum. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3522891]