Planar nanocontacts with atomically controlled separation

TL;DR

This paper presents a method for creating stable, atomically controlled nanogaps in gold contacts on an oxidized aluminium substrate, enabling studies of molecular conductance with tunable electronic properties.

Contribution

The authors developed a reproducible technique for fabricating atomically precise nanogaps with integrated gating, allowing stable measurements of molecular conductance at room and low temperatures.

Findings

Deposition of conjugated molecules increases gap conductance significantly.

Room temperature I-V characteristics are slightly nonlinear.

Low temperature I-V characteristics are highly nonlinear with a clear gate effect.

Abstract

We have developed a technology to reproducibly make gaps with distance control on the single atom scale. The gold contacts are flat on the nanometre scale and are fabricated on an oxidized aluminium film that serves as a gate. We show that these contacts are clean and can be stabilized via chemical functionalization. Deposition of conjugated molecules leads to an increase in the gap conductance of several orders of magnitude. Stable current-voltage characteristics at room temperature are slightly nonlinear. At low temperature, they are highly nonlinear and show a clear gate effect.