Energetic Stabilities, Structural and Electronic Properties of Monolayer Graphene Doped with Boron and Nitrogen Atoms

Seba Varghese,Vikas Mittal,Krishna Singh,Sundaram Swaminathan

doi:10.3390/electronics5040091

Abstract

The structural, energetic, and electronic properties of single-layer graphene doped with boron and nitrogen atoms with varying doping concentrations and configurations have been investigated here via first-principles density functional theory calculations. It was found that the band gap increases with an increase in doping concentration, whereas the energetic stability of the doped systems decreases with an increase in doping concentration. It was observed that both the band gaps and the cohesive energies also depend on the atomic configurations considered for the substitutional dopants. Stability was found to be higher in N-doped graphene systems as compared to B-doped graphene systems. The electronic structures of B- and N-doped graphene systems were also found to be strongly influenced by the positioning of the dopant atoms in the graphene lattice. The systems with dopant atoms at alternate sublattices have been found to have the lowest cohesive energies and therefore form the most stable structures. These results indicate an ability to adjust the band gap as required using B and N atoms according to the choice of the supercell, i.e., the doping density and substitutional dopant sites, which could be useful in the design of graphene-based electronic and optical devices.

Highlights

Graphene, a single atomic layer of graphite which exhibits exceptional structural, mechanical, electrical, optical, and chemical properties, has applications in numerous fields [1]
It was observed that both B- and N-doped graphene maintain the planar geometry of pristine graphene with a slight distortion with longer C–B bonds and shorter C–N bonds compared to the C–C bond length, which is in agreement with previous reports
The doped structures with dopant atoms placed at adjacent locations have been found to be highly distorted, with less distortion in N-doped graphene systems compared to that of the corresponding B-doped graphene systems

Summary

Introduction

A single atomic layer of graphite which exhibits exceptional structural, mechanical, electrical, optical, and chemical properties, has applications in numerous fields [1]. Graphene has attracted the attention of researchers from both experimental and theoretical points of view after its successful isolation in 2004 [2], especially for electronics owing to its exceptional properties [3] such as ballistic electron transport at room temperature [4], high charge carrier mobility [5], room-temperature fractional quantum Hall effect [6], and finite electrical conductivity at zero charge carrier density [7] These features of graphene that make it a potential candidate for future nanoelectronics [8,9] arise from its unique zero energy band gap with linear energy-momentum relation around the Dirac point [10,11]. Various approaches such as application of an external electric field [12], chemical functionalization [13], use of graphene nanoribbons [14], and doping with heteroatoms [15]

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Results

Conclusion