In this study, first-principles time-dependent density functional theory calculations were used to demonstrate the possibility to modulate the amplitude of the optical electric field (E-field) near a semiconducting graphene nanoribbon. A significant enhancement of the optical E-field was observed 3.34 Å above the graphene nanoribbon sheet, with an amplitude modulation of approximately 100 fs, w...

Semi-analytical model for carbon nanotube and graphene nanoribbon transistors

Graphene, a recently discovered form of carbon, has received much attention over the past few years due to its excellent electrical, optical, and thermal properties [1]. With an extraordinary carrier mobility and high current density [2], graphene's application in electronic devices is promising. As a zero bandgap material, pristine graphene cannot be used as a semi-conducting channel in transi...

Graphene nanoribbons (GNRs), as an emerging class of material, hold great potential for the future high speed and low power electronic and spintronic devices. The fabrication of GNRs is of the utmost interest in terms of graphene based device research. Chemical narrowing of GNRs by oxidation is a promising technique in producing nanoribbons of desired widths. In this article, we hope to elucida...

Graphene nanostructures, where quantum confinement opens an energy gap in the band structure, hold promise for future electronic devices. To realize the full potential of these materials, atomic-scale control over the contacts to graphene and the graphene nanostructure forming the active part of the device is required. The contacts should have a high transmission and yet not modify the electron...

Optical gradient forces between monolayer infinite-width graphene sheets as well as single-mode graphene nanoribbon pairs of graphene surface plasmons (GSPs) at mid-infrared frequencies were theoretically investigated. Although owing to the strongly enhanced optical field, the normalized optical force, fn, can reach 50 nN/μm/mW, which is the largest fn as we know, the propagation loss is also l...

We propose a graphene nanoribbon-based heterojunction, where a defect-free interface separates two zigzag graphene nanoribbons prepared in opposite antiferromagnetic spin configurations. This heterospin junction is found to allow the redirecting of low-energy electrons from one edge to the other. The basic scattering mechanisms and their relation to the system’s geometry are investigated throug...

Graphene nanoribbons are the counterpart of carbon nanotubes in graphene-based nanoelectronics. We investigate the electronic properties of chemically modified ribbons by means of density functional theory. We observe that chemical modifications of zigzag ribbons can break the spin degeneracy. This promotes the onset of a semiconducting-metal transition, or of a half-semiconducting state, with ...