Electrostatic doping of graphene through ultrathin hexagonal boron nitride films

TL;DR

This study uses first-principles calculations to explore how ultrathin hexagonal boron nitride layers influence electrostatic doping in graphene, revealing intrinsic doping effects and key parameters for device design.

Contribution

The paper introduces an analytical model linking h-BN thickness and applied potential to graphene doping, highlighting the role of interface effects and predicting observable intrinsic doping.

Findings

Intrinsic doping is prominent for ultrathin h-BN layers.

Doping depends on h-BN thickness and applied potential.

Interface terms significantly influence doping behavior.

Abstract

When combined with graphene, hexagonal boron nitride (h-BN) is an ideal substrate and gate dielectric with which to build metalh-BN|graphene field-effect devices. We use first-principles density functional theory (DFT) calculations for Cu|h-BN|graphene stacks to study how the graphene doping depends on the thickness of the h-BN layer and on a potential difference applied between Cu and graphene. We develop an analytical model that describes the doping very well, allowing us to identify the key parameters that govern the device behaviour. A predicted intrinsic doping of graphene is particularly prominent for ultrathin h-BN layers and should be observable in experiment. It is dominated by novel interface terms that we evaluate from DFT calculations for the individual materials and for interfaces between h-BN and Cu or graphene.