Effects of edge passivation by hydrogen on electronic structure of armchair graphene nanoribbon and band gap engineering

We investigated effects of hydrogen passivation of edges of armchair graphene nanoribbons (AGNRs) on their electronic properties using first-principles method. The calculated band gaps of the AGNRs vary continually over a range of 1.6 eV as a function of a percentage of sp(3)-like bonds at the edges. This provides a simple way for band gap engineering of graphene as the relative stability of sp(2) and sp(3)-like bonds at the edges of the AGNRs depends on the chemical potential of hydrogen gas, and the composition of the sp(2) and sp(3)-like bonds at the edges of the AGNRs can be easily controlled experimentally via temperature and pressure of H-2 gas.