Influence of Be vacancy on 2D BeN₄ single-layer for enhanced H₂S sensing: prediction from first-principles simulations

A notable surge in research interest directed towards the exploration and development of two-dimensional materials, specifically in the realm of advancing nano-devices, with a special focus on applications in gas detection, has been observed. Among these materials, the spotlight has fallen on a newly synthesized single-layered Dirac Semimetal, known as BeN 4 , which holds great promise as a potential candidate for an efficient gas sensor. The current investigation uses first-principles calculations to examine the H 2 S detection capability of pristine and point-defect-tempted BeN 4 single-layers. The H 2 S molecule has been observed to be weakly adsorbed on pure BeN 4 through weak van der Waals interaction exhibiting very low adsorption energy of −0.0726 eV and insignificant charge transport. The impact of the Be vacancy point defect in BeN 4 was the surge in H 2 S adsorption energy to −0.582 eV, manifested by enhanced charge transmission (0.02 e) from the H 2 S molecule to the BeN 4 with Be defects. The reasonable physical steadiness and modest recovery time (6 ms) at ambient conditions indicate the possibility of Be point-defected BeN 4 being a contender as a sensor material for designing and developing a robust H 2 S gas sensor. In addition, the sensor exhibited a selective response towards the H 2 S gas molecules. Our findings will provide a reference line for the fabrication of innovative H 2 S detectors, showcasing the practical implications of the observed enhancements in H 2 S adsorption energy and charge transmission in Be point-defected BeN 4 structures.