Strong anisotropy and band Gap engineering with mechanical strains in two-dimensional orthorhombic diboron dinitride (O-B2N2)

Abstract

Tuning two-dimensional (2D) nanomaterial's structural and electronic properties has facilitated the new research paradigm in electronic device applications. In this work, the first-principles density functional theory (DFT) based methods are used to investigate the structural, electronic, and transport properties of an orthorhombic diboron dinitride (o-B2N2)-based polymorph. Interestingly, it depicts a low bandgap semiconducting nature with a robust anisotropic behaviour compared to the hexagonal boron nitride (h-BN), which is an insulator and isotropic. We can also tune the structural and electronic properties of the semiconducting o-B2N2-based structure through an external in-plane mechanical strain. Further, by employing the Landauer-B u¨ ttiker approach, the electronic transmission function [T(E)], and electric current (I) calculations reveal that the boron nitride-based polymorph shows a robust direction-dependent anisotropy of the quantum transport properties. We have demonstrated the direction-dependence of the electric current in two perpendicular directions (Ix and Iy), where we have observed an electric current ratio (η=Ix/Iy) of around 61.75 at 0.8 V. All these findings, such as directional-dependence anisotropy in [T(E)], I - V characteristics, and bandgap tunning, suggest that the applicability of such B2N2 based monolayer can be promising for futuristic electronic device applications. © 2022 Elsevier B.V.