Electric field effect in boron and nitrogen doped graphene bilayers

TL;DR

This study uses density functional theory to explore how external electric fields influence the electronic properties and energy gap of boron and nitrogen doped bilayer graphene, revealing tunable conduction characteristics.

Contribution

It demonstrates how electric fields can modulate doping effects and electronic properties in bilayer graphene, providing insights for field-effect device applications.

Findings

Electric fields can tune the energy gap in doped bilayer graphene.

Doping and electric field together influence the Fermi level and conductivity.

External electric fields can effectively control the doping effects in graphene bilayers.

Abstract

Unlike single layer graphene, in the case of $AB$-stacked bilayer graphene (BLG) one can induce a non-zero energy gap by breaking the inversion symmetry between the two layers using a perpendicular electric field. This is an essential requirement in field-effect applications, particularly since the induced gap in BLG systems can be further tuned by the magnitude of the external electric field. Doping is another way to modify the electronic properties of graphene based systems. We investigate here BLG systems doped with boron and nitrogen in the presence of external electric field, in the framework of density functional theory (DFT) calculations. Highly doped BLG systems are known to behave as degenerate semiconductors, where the Fermi energy depends on the doping concentration but, in addition, we show that the electronic properties drastically depend also on the applied electric field. By changing the magnitude and the orientation of the electric field, the gap size and position relative to the Fermi level may be tuned, essentially controlling the effect of the extrinsic doping. In this context, we discuss in how far the external electric field may suitably adjust the effective doping and, implicitly, the conduction properties of doped BLG systems.