High switching ratio and inorganic gas sensing performance in BeN4 based nanodevice: a first-principles study

Abstract

Recently, Dirac material BeN4 has been synthesized by using laser-heated diamond anvil-groove technology (Bykov et al 2021 Phys. Rev. Lett. 126 175501). BeN4 layer, i.e. beryllonitrene, represents a qualitatively class of two-dimensional (2D) materials that can be built of a metal atom and polymeric nitrogen chains, and hosts anisotropic Dirac fermions. Enlighten by this discovered material, we study the electronic structure, anisotropic transport properties and gas sensitivity of 2D BeN4 using the density functional theory combined with non-equilibrium Green’s function method. The results manifest that the 2D BeN4 shows a typical semi-metallic property. The electronic transport properties of the intrinsic BeN4 devices show a strong anisotropic behavior since electrons transmitting along the armchair direction is much easier than that along the zigzag direction. It directly results in an obvious switching characteristic with the switching ratio up to 105. Then the adsorption characteristics indicate that H2S, CO, CO2 and H2 molecules are physisorption, while the NH3, NO, NO2, SO2 molecules are chemisorption. Among these chemisorption cases, the 2D gas sensor devices show an extremely high response for SO2 recognition, and the high anisotropy of the original 2D BeN4 device still maintains after adsorbing gas molecules. Finally, high switching ratio and inorganic gas sensing performance of BeN4 monolayer could be clearly understood with local density of states, bias-dependent spectra, scattered state distribution. In general, the results indicate that the designed BeN4 devices have potential practical application in high-ratio switching devices and high gas-sensing molecular devices.