Electronic and transport properties in geometrically disordered graphene antidot lattices

TL;DR

This study uses advanced simulations to show how disorder in graphene antidot lattices affects their electronic properties, revealing that imperfections can induce a transport gap through Anderson localization, impacting device performance.

Contribution

The paper demonstrates how geometric disorder in graphene antidot lattices leads to a transport gap via Anderson localization, with detailed analysis of defect effects on electronic transport.

Findings

Disorder can induce a transport gap through Anderson localization.

The transport gap size scales with antidot radius and lattice periodicity.

Positional randomness of antidots is more detrimental than size randomness.

Abstract

A graphene antidot lattice, created by a regular perforation of a graphene sheet, can exhibit a considerable band gap required by many electronics devices. However, deviations from perfect periodicity are always present in real experimental setups and can destroy the band gap. Our numerical simulations, using an efficient linear-scaling quantum transport simulation method implemented on graphics processing units, show that disorder that destroys the band gap can give rise to a transport gap caused by Anderson localization. The size of the defect induced transport gap is found to be proportional to the radius of the antidots and inversely proportional to the square of the lattice periodicity. Furthermore, randomness in the positions of the antidots is found to be more detrimental than randomness in the antidot radius. The charge carrier mobilities are found to be very small compared to values found in pristine graphene, in accordance with recent experiments.