▎ 摘　　要

The evolution of electronic structures of hydrogenated graphene with different amount of hydrogen (H) coverage was investigated by ultraviolet photoemission spectroscopy and optical absorption spectroscopy. Raman spectroscopy and x-ray photoelectron spectroscopy were used to monitor and evaluate the H coverage. At low H coverage, the sp(3) C-H bonds embedded within a sp(2) C matrix behave as defects in graphene and depress the delocalized pi electron system. At high H coverage, two localized pi electron states originating from the sp(2) C clusters encircled by the sp(3) C-H matrix appear in the electronic band structures, and an opening of a band gap has been observed. (C) 2010 American Institute of Physics. [doi:10.1063/1.3524217]