Electronic transport properties of graphene channel with metal electrodes or insulating substrates in 10 nm-scale devices

Abstract

We have studied the electronic transport properties of armchair graphene nanoribbons (AGNRs) bridged between two metal electrodes or supported on insulating substrates in 10 nm-scale devices using the first-principles calculations. The two metal species of Ti and Au are examined as metal electrodes and are compared. The current densities through the AGNR-Ti contact are about 10 times greater than those through the AGNR-Au contact, even though the AGNR width reaches 12 nm. For the insulating substrates, we have investigated the dependence of the channel length on the transport properties using models with two channel lengths of 15.1 and 9.91 nm. Regardless of the channel length, the on/off current ratio is 10 5 for the AGNRs on an O-terminated surface. This ratio is consistent with the recent experiments and is less by factors of 10 16 for the 15.1 nm channel length and 10 8 for the 9.91 nm channel length compared to the freestanding AGNR.

Efficient calculation of the Green's function in scattering region for electron-transport simulations

“…Thus far, to circumvent this restriction, transport calculations for large systems containing several thousands of atoms have been performed within atomic-basis formalism and tight-binding (TB) formalism based on DFT. [9][10][11][12] Since the Hamiltonian matrix is dense in these formalisms, the computational cost of the inverse matrix for obtaining the Green's function matrix by the direct method is proportional to the cube of the matrix dimension. Moreover, there are unavoidable problems such as the incompleteness of basis sets and inefficiency in parallel computing.…”

Template synthesis of armchair-edge graphene nanoribbons inside carbon nanotubes

“…raphene nanoribbons (GNRs), one-dimensional carbon strips with nanometer width, have been drawing much attention due to their unique electronic and magnetic properties. [1][2][3][4][5][6][7] Since the band structures of GNRs depend on their widths and edge configurations, [8][9][10][11][12] bottom-up synthetic methods from small precursor molecules are widely investigated for uniform GNR fabrication. [13][14][15][16][17][18][19] Among the various synthetic approaches, nano-templated growth using the inner spaces of carbon nanotubes (CNTs) is a useful method to precisely control the width of GNRs.…”