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

Abstract

A notable surge in research interest directed towards the exploration and development of two-dimensional (2D) 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 BeN4, which holds great promise as a potential candidate for an efficient gas sensor. The current investigation uses first-principles calculations to examine the H2S detection capability of pristine and point-defect-tempted BeN4 single-layers. The H2S molecule has been observed to be weakly adsorbed on pure BeN4 through weak Van der Waals (vdW) interaction exhibiting very low adsorption energy of -0.0726 eV and insignificant charge transport. The impact of the Be vacancy point defect in BeN4 was the surge in H2S adsorption energy to -0.582 eV, manifested by enhanced charge transmission (0.02e) from the H2S molecule to the BeN4 with Be defects. The reasonable physical steadiness and modest recovery time (6 ms) at ambient conditions indicate the possibility of Be point-defected BeN4 being a contender as a sensor material for designing and developing a robust H2S gas sensor. In addition, the sensor exhibited a selective response towards the H2S gas molecules. Our findings will provide a reference line for the fabrication of innovative H2S detectors, showcasing the practical implications of the observed enhancements in H2S adsorption energy and charge transmission in Be point-defected BeN4 structures.