Influence of vacancy defects on 2D BeN4 monolayer for NH3 adsorption: A density functional theory investigation.

Two-dimensional (2D) materials have attracted a great deal of interest in developing nanodevices for gas-sensing applications over the years. The 2D BeN4 monolayer, a recently synthesized single-layered Dirac semimetal, has the potential to function as a gas sensor. This study analyses the ammonia (NH3) sensing capacity of the pristine and vacancy-induced BeN4 monolayers using first-principle density functional theory (DFT) calculations. As per the obtained results, the NH3molecule is adsorbed on pristine BeN4 via weak Van der Waals interaction (vdW) with a poor adsorption energy of -0.41 eV and negligible charge transfer. Introducing Be vacancy in BeN4 increases the NH3 adsorption energy to -0.83 eV due to improved charge transfer (0.044e) from defective monolayer to the NH3 molecule. The structural stability, suitable recovery time (74 s) at room temperature, and superior work function sensitivity promise the potential application of defective BeN4 as an NH3 sensor. This research will be a theoretical groundwork for creating innovative BeN4-based NH3 gas sensors.