Electronic Transport in Graphene with Aggregated Hydrogen Adatoms

TL;DR

This paper investigates how aggregation of hydrogen adatoms on graphene influences electronic transport, revealing that aggregation significantly enhances conductance and extends localization lengths, with implications for graphene-based electronic devices.

Contribution

It introduces a model linking adatom aggregation to transport properties, demonstrating how aggregation modifies conductance and localization in graphene.

Findings

Aggregation increases conductance by several orders of magnitude.

Larger adatom clusters extend the Anderson localization length.

Effective adatom concentration $x^\star$ describes transport across distributions.

Abstract

Hydrogen adatoms and other species covalently bound to graphene act as resonant scattering centers affecting the electronic transport properties and inducing Anderson localization. We show that attractive interactions between adatoms on graphene and their diffusion mobility strongly modify the spatial distribution, thus fully eliminating isolated adatoms and increasing the population of larger size adatom aggregates. Our scaling analysis shows that such aggregation of adatoms increases conductance by up to several orders of magnitude and results in significant extension of the Anderson localization length in the strong localization regime. We introduce a simple definition of the effective adatom concentration $x^\star$ , which describes the transport properties of both random and correlated distributions of hydrogen adatoms on graphene across a broad range of concentrations.