Selective highly sensitive gas sensing by using the BeP2C monolayer: a theoretical study

Abstract

Identifying high-performance materials is essential for developing new gas sensors capable of detecting harmful gases. In this study, density functional theory (DFT) and the non-equilibrium Green's function (NEGF) method were employed to investigate the gas-sensitive properties of BeP₂C monolayer films. The structural, electronic, transport and gas sensitivity characteristics of the BeP₂C monolayer were examined for various adsorbed gases, including CO, CO₂, NH₃, NO, NO₂, H₂S, SO₂, H₂O and O₂. Except for CO₂ and O₂, all other gases are bound to the substrate via ionic bonds, with SO₂ additionally forming covalent bonds. Notably, NO, NO₂ and SO₂ have suitable adsorption energy on the BeP₂C monolayer and can change the electronic properties of the material. Current–voltage (I–V) characteristics and transport functions reveal that the BeP₂C monolayer exhibits high sensitivity and selectivity towards NO, NO₂ and SO₂ gases. The relative change in the work function for NO adsorbed on the BeP₂C monolayer is 10.14%, indicating its promising potential as a work-function type gas sensor for detecting NO. The BeP₂C monolayer is a high-performance, reusable gas sensor that can detect NO (2.61 ms) at room temperature and NO₂ (3.83 s) at 400 K. Furthermore, due to its high adsorption energy, the BeP₂C monolayer is also capable of capturing SO₂. This study provides a theoretical foundation for the application of BeP₂C in gas sensor technology.