Engineering the work function of armchair graphene nanoribbons using strain and surface functional species: a first principles study

Abstract

First principles density-functional theory calculations were performed to study the effects of strain, edge passivation, and surface functional species on the structural and electronic properties of armchair graphene nanoribbons (AGNRs) with a particular focus on the work function. The work function was found to increase with uniaxial tensile strain while decreasing with compression. The variation of the work function under strain is primarily due to the shift of the Fermi energy with strain. In addition, the relationship between the work function variation and the core level shift with strain is discussed. Distinct trends of the core level shift under tensile and compressive strain were discovered. For AGNRs with the edge carbon atoms passivated by oxygen, the work function is higher than for nanoribbons with the edge passivated by hydrogen under a moderate strain. The difference between the work functions in these two edge passivations is enlarged (reduced) under a sufficient tensile (compressive) strain. This has been correlated to a direct-indirect band gap transition for tensile strains of about 4% and to a structural transformation for large compressive strains at about -12%. Furthermore, the effect of the surface species decoration, such as H, F, or OH with different covering density, was investigated. It was found that the work function varies with the type and coverage of surface functional species. F and OH decoration increase the work function while H decreases it. The surface functional species were decorated on either one side or both sides of AGNRs. The difference in the work functions between one-side and two-side decorations was found to be relatively small, which may suggest an introduced surface dipole plays a minor role.

arXiv comment10 pages, 9 figures, and 1 table

References in corpus (13)

• Electric Field Effect in Atomically Thin Carbon Films
• Two-Dimensional Gas of Massless Dirac Fermions in Graphene
• Energy Gaps in Graphene Nanoribbons
• Doping graphene with metal contacts
• Graphane: a two-dimensional hydrocarbon
• Tuning the graphene work function by electric field effect
• First-principles study of the interaction and charge transfer between graphene and metals
• All-graphene integrated circuits via strain engineering
• Effects of Strain on Electronic Properties of Graphene
• First-principles investigation of graphene fluoride and graphane
• First Principles Study of Work Functions of Single Wall Carbon Nanotubes
• Strain modulated band gap of edge passivated armchair graphene nanoribbons
• Buckled circular monolayer graphene: a graphene nano-bowl

Cited by in corpus (5)

• Strain engineered direct-indirect band gap transition and its mechanism in 2D phosphorene
• The impact of edges and dopants on the work function of graphene nanostructures. The way to high electronic emission from pure carbon medium
• Electronic structure of oxygen-functionalized armchair graphene nanoribbons
• Conductance across strain junctions in graphene nanoribbons
• A new 2D auxetic CN2 nanostructure with high energy density and mechanical strength