On the Factor responsible for Electron-Hole Conduction Asymmetry in Monolayer Graphene

Pawan Kumar Srivastava, Swasti Arya, Santosh Kumar, Subhasis Ghosh

Published 2016-08-20Version 1

We report electron-hole conduction asymmetry in devices based on monolayer graphene. In several reports, electron-hole conduction asymmetry in graphene has been attributed to imbalanced carrier injection from metallic electrodes. We have also tested this conjecture and it has been observed that metallic contacts have negligible impact on asymmetric conduction. Electrical measurements show that monolayer graphene based devices those exhibit suppressed electron conduction also display n-type doping i.e. presence of donor impurities in graphene which scatter electrons more efficiently and is in agreement with previous reports. We have discussed our results in terms of transport measurements on graphene devices and Raman spectroscopic measurements. To reconcile our observation we have correlated our findings with a theoretical model describing dependence of scattering cross section on sign of scattering potential which is a manifestation of relativistic nature of carriers in graphene.