Influence of vacancy defects on 2D BeN₄monolayer for NH₃adsorption: a density functional theory investigation

Two-dimensional materials have attracted a great deal of interest in developing nanodevices for gas-sensing applications over the years. The 2D BeN₄monolayer, a recently synthesized single-layered Dirac semimetal, has the potential to function as a gas sensor. This study analyzes the NH₃sensing capacity of the pristine and vacancy-induced BeN₄monolayers using first-principles density functional theory (DFT) calculations. As per the results, the NH₃molecule is physisorbed on the pristine BeN₄via weak Van der Waals interaction with a poor adsorption energy of -0.41 eV and negligible charge transfer. Introducing Be vacancy in BeN₄increased the NH₃adsorption energy to -0.83 eV due to the improved charge transfer (0.044 e) from the defective monolayer to the NH₃molecule. The structural stability, sufficient recovery time (74 s) at room temperature, and superior work function sensitivity promise the potential application of defective BeN₄as an NH₃sensor. This research will be a theoretical groundwork for creating innovative BeN₄-based NH₃gas sensors.