Chemical Doping and Electron-Hole Conduction Asymmetry in Graphene Devices

TL;DR

This study explores how chemical doping with polyethylene imine and diazonium salts affects electron-hole conduction asymmetry in graphene devices, revealing that doping can selectively preserve or reduce conductance for different carriers.

Contribution

It demonstrates that specific chemical dopants induce conduction asymmetry in graphene, supported by simulations explaining the underlying mechanism of imbalanced carrier injection.

Findings

Doping with polyethylene imine and diazonium salts causes conduction asymmetry.

One carrier's conductance remains stable while the other's decreases.

Simulations attribute asymmetry to electrode-channel neutrality point misalignment.

Abstract

We investigate polyethylene imine and diazonium salts as stable, complementary dopants on graphene. Transport in graphene devices doped with these molecules exhibits asymmetry in electron and hole conductance. The conductance of one carrier is preserved, while the conductance of the other carrier decreases. Simulations based on nonequilibrium Green's function formalism suggest that the origin of this asymmetry is imbalanced carrier injection from the graphene electrodes caused by misalignment of the electrode and channel neutrality points.