▎ 摘　　要

Hydrogenation has proven to be an effective tool to open the band gap of graphene. In the present density functional study, we demonstrate that single-side-hydrogenated graphene is a semiconductor with an indirect band gap of 1.35 eV, which is in between the gapless graphene and wide band-gap graphane and surprisingly close to silicon. We show that its electronic structure and lattice characteristics are substantially different from those of graphene, graphone, or graphane. The lattice parameter and C-C bond length are found to be lengthened by 15% of those of graphene. Our binding-energy analysis confirms that such a single-sided hydrogenation leads to energetically stable material, making it a promising candidate as an organic semiconductor.