Enhanced Conductance Fluctuation by Quantum Confinement Effect in Graphene Nanoribbons

TL;DR

This study reveals that quantum confinement in graphene nanoribbons significantly enhances conductance fluctuations, which can be used to electrically probe their band structure despite disorder effects.

Contribution

It demonstrates a correlation between conductance fluctuation and density-of-states in GNR, providing a new method to analyze band structures via low-frequency noise measurements.

Findings

Conductance fluctuation correlates with density-of-states in GNR.

Noise peaks match subband positions in GNR band structure.

Quantum confinement enhances conductance fluctuation in GNR.

Abstract

Conductance fluctuation is usually unavoidable in graphene nanoribbons (GNR) due to the presence of disorder along its edges. By measuring the low-frequency noise in GNR devices, we find that the conductance fluctuation is strongly correlated with the density-of-states of GNR. In single-layer GNR, the gate-dependence of noise shows peaks whose positions quantitatively match the subband positions in the band structures of GNR. This correlation provides a robust mechanism to electrically probe the band structure of GNR, especially when the subband structures are smeared out in conductance measurement.