Electronic Transport Properties of Graphene Channel between Au Electrodes

Abstract

We study the electronic transport properties of armchair graphene nanoribbons with a width of up to 12 nm bridged between two Au electrodes using first-principles calculations. The transport properties sensitively depend on the ribbon width, even though the width reaches 12 nm. The variation of transport properties is ascribed to the detailed electronic structures of graphene ribbons, which sensitively depend on their width. The band structure and the symmetry of π state of the graphene play important roles in determining the transport properties.

Platinum atomic contacts: From tunneling to contact

“…We performed electron transport calculations by means of the NEGF extension of the OpenMX code, 29 which is by now widely used. [38][39][40][41][42][43] The model implemented in this software makes use of periodic boundary conditions. The basis sets employed consist of linear combinations of atomic orbitals generated by a confinement scheme which yields wave functions with zero value beyond a chosen cutoff radius.…”

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

“…The symmetry of the p state of the AGNRs also contributes to reduce the currents with the Au electrodes. 14 We have found that the currents in the AGNR-Ti contact are over 10 times as great as those in the AGNR-Au contact, even though the AGNR width reaches 12 nm. Nevertheless, the experiment has reported that the Ti contact results in higher contact resistance values (R c ¼ 48.0 6 5.7 kX lm) compared to the Au contact (R c ¼ 3.9 6 1.5 kX lm).…”

“…The high carrier mobility allows the material to be applied to the high-speed electronic devices in the post-silicon era. On the other hand, the electronic properties of graphene are significantly fragile against the surrounding foreign materials, such as metal electrodes [1][2][3][4][5][6][7][8][9][10][11][12][13][14] and insulating substrates. [15][16][17][18][19][20][21][22][23][24][25][26] This is because the whole area of graphene intrinsically forms interfaces with such foreign materials.…”

“…7,8,10 The transport properties have also been studied actively. [11][12][13][14] It was found that the contact resistance of the Ni-graphene system is one order of magnitude lower than that of Cu-graphene for graphene channels of a few nm in length. 12 We previously reported that currents sensitively depend on the width of armchair graphene nanoribbons (AGNRs) up to 12 nm for the Au-graphene hybrid structures using the first-principles electronic transport calculations.…”

“…12 We previously reported that currents sensitively depend on the width of armchair graphene nanoribbons (AGNRs) up to 12 nm for the Au-graphene hybrid structures using the first-principles electronic transport calculations. 14 However, the dependence of the transport properties on metal species has not yet been ascertained for AGNRs over 10 nm in width.…”