The Effect of Cluster Formation on Graphene Mobility

TL;DR

This study explores how gold atom clusters influence graphene's electrical mobility, revealing that clustering at room temperature improves mobility compared to dispersed impurities, with implications for graphene device optimization.

Contribution

It demonstrates that gold cluster formation on graphene enhances mobility and shifts the Dirac point, providing new insights into impurity effects on graphene transport properties.

Findings

Clustering of gold atoms increases graphene mobility.

Room temperature promotes gold atom clustering.

Clustering shifts the Dirac point towards zero.

Abstract

We investigate the effect of gold (Au) atoms in the form of both point-like charged impurities and clusters on the transport properties of graphene. Cryogenic deposition (18 K) of Au decreases the mobility and shifts the Dirac point in a manner that is consistent with scattering from point-like charged impurities. Increasing the temperature to room temperature promotes the formation of clusters, which is verified with atomic force microscopy. We find that for a fixed amount of Au impurities, the formation of clusters enhances the mobility and causes the Dirac point to shift back towards zero.