Low-bias Negative Differential Resistance effect in armchair graphene nanoribbon junctions

TL;DR

This paper demonstrates a low-bias negative differential resistance effect in armchair graphene nanoribbon junctions, which is robust and tunable, with potential applications in nanoelectronic devices.

Contribution

It reveals a novel NDR effect in AGNR junctions driven by bias voltage, showing robustness against structural variations and low operational bias.

Findings

NDR effect occurs at bias as low as ~0.2 V

NDR is robust against structural and fabrication variations

Valley current nearly vanishes at the NDR point

Abstract

Graphene nanoribbons with armchair edges (AGNRs) have bandgaps that can be flexibly tuned via the ribbon width. A junction made of a narrower AGNR sandwiched between two wider AGNR leads was recently reported to possess two perfect transmission channels close to the Fermi level. Here, we report that by using a bias voltage to drive these transmission channels into the gap of the wider AGNR lead, we can obtain a negative differential resistance (NDR) effect. Owing to the intrinsic properties of the AGNR junctions, the on-set bias reaches as low as ~ 0.2 V and the valley current almost vanishes. We further show that such NDR effect is robust against details of the atomic structure of the junction, substrate and whether the junction is made by etching or by hydrogenation.