Sub-Nanometer Width Armchair Graphene Nanoribbon Energy Gap Atlas

Abstract

Extended all-sp 2 -carbon macromolecules have the potential to replace silicon in integrated nanometer-scale devices. Up to now, studies on the electronic properties of such structures, for example, graphene nanoribbons, have been focused mostly on the infinitely long limit, which is inadequate when approaching future devices with sub-10 nm control. Moreover, their electronic variation has not been systematically assessed as a function of chemically diverse edge termini. Such knowledge is central when prototyping potential allcarbon circuits. Here, we present a graphene nanoribbon energy gap atlas based on density functional tight-binding spin-polarized calculations of nearly ten thousand randomly generated nanoribbons with a maximal nominal width of 1 nm and an armchair long edge. We classify ribbon families and show that their energy levels are strongly dependant on their termini edge states. We notably reveal modulation of the bulk energy gap by 0.3 eV through minimal edge modifications and put forward simple rules for inducing antiferromagnetic edge states.

Thermal transmittance in graphene based networks for polymer matrix composites

“…Thermal conductivity of GNRs with lengths ranging from 20 to 1000 nm and width xed to 2.4 nm is then calculated by MD simulations. These dimensions are in the range of both modeling [39,40] and experimental [41,42] studies in the literature, which recently focused the attention on graphene nanoribbons with sub-10-nanometers widths. The simulation box is divided into slabs along…”

Synthesis of Graphene Nanoribbons by Ambient-Pressure Chemical Vapor Deposition and Device Integration

“…[4][5] It has been predicted by theoretical studies that narrow (<10 nm) graphene nanoribbons (GNRs) with armchair-type edges exhibit semiconducting behavior, due to the intense quantum confinement and edge effects. [6][7][8] Whereas the predominant "top-down" approaches, such as lithographical patterning of graphene [9][10] and unzipping of carbon nanotubes [11][12] can hardly control the width and edge structure of GNRs, surface-assisted [13][14][15] and solution-mediated [16][17][18][19][20] "bottom-up" methods have been developed to synthesize atomically precise GNRs. Such "bottomup" synthesized ultranarrow (~1-2 nm) GNRs have demonstrated large bandgaps of ~1 to 2 eV with visible to near-infrared absorption, [16][17][18][19][20][21][22][23] rendering them highly interesting for a broad range of applications in next-generation transistors, as well as optoelectronic and photonic devices.…”

Optical properties of graphene nanoflakes: Shape matters

“…It was been shown that structures with zigzag edge are magnetic 47,48,59,60 . Therefore, spin-polarized calculations were carried out for all the TZZ systems and the two largest HZZ systems using the DFTB implementation for collinear spin polarization 54 .…”