Atomic-scale Mechanisms of Growth and Doping of Graphene Nano-Ribbons

摘要

Control over structural and electronic properties of graphene samples is necessary for the fabrication of nano-electronic devices. Here we report the results of first-principles quantum-mechanical studies on the growth and doping of graphene nanoribbons (GNR). We find that hydrogenation of open-ended carbon nanotubes (CNT) can lead to successive breaking of tip C-C bonds. If enough hydrogen atoms are supplied then the CNTs unzip to GNRs with specific widths and edge morphologies. We also examine the possibilities that ammonia-related species can inject carriers in graphene. We show that NH3 molecules have a complex dynamics on graphene. Annealing in ammonia can result in the formation of donors on the graphene basal plane, or the de-activation of dopants on graphene and at GNR edges. The results explain available experimental data and suggest new ways to optimize the properties and performance of GNR-based systems.