Edges of graphene nanoribbons with adsorbates

Full text: In order to build electronic components using graphene a band gap needs to be obtained. One way of achieving this is by restricting the structures in space to finite width, for example as a nanoribbon. They expose edges that are usually highly reactive and thus would easily adsorb atoms from the gas phase. We have studied the stability of carbon nanoribbons exposed to various elements and molecules, including hydrogen and oxygen, water and ammonia, using thermodynamical considerations. The total energies were obtained by total energy calculations employing the density-functional theory. We report the various structures found to be stable at different temperatures and pressures, and analyse the electronic structure evaluating quantities that could be experimentally verified. (author)