Ordered Semiconducting Nitrogen-Graphene Alloys

TL;DR

This study investigates nitrogen-doped graphene, revealing stable ordered structures with semiconducting properties, including a direct band gap material, using first principles calculations and optimization techniques.

Contribution

It identifies two stable nitrogen-doped graphene structures, C3N and C12N, with C12N exhibiting a direct band gap, advancing the understanding of doped graphene's electronic properties.

Findings

C12N has a direct band gap of 0.98 eV.

Nitrogen dopants exhibit repulsive interactions, preventing full phase separation.

Two stable ordered N-doped graphene structures were discovered.

Abstract

The interaction between substitutional nitrogen atoms in graphene is studied by performing first principles calculations. The nearest neighbor interaction between nitrogen dopants is highly repulsive because of the strong electrostatic repulsion between nitrogen atoms, which prevents the full phase separation in nitrogen doped graphene. Interestingly, there are two relatively stable nitrogen-nitrogen pairs due to the anisotropy charge redistribution induced by nitrogen doping. We reveal two stable semiconducting ordered N doped graphene structures C3N and C12N through the cluster expansion technique and particle swarm optimization method. In particular, C12N has a direct band gap of 0.98 eV. The heterojunctions between C12N and graphene nanoribbons might be promising organic solar cells.