Two‐Dimensional α‐SbN: A Promising Material for High‐Performance and Reversible NO ₂ Sensing Revealed by First‐Principles Study

Recently, a new class of two‐dimensional (2D) group‐VA binary materials, known as 2D V–V compounds, has attracted considerable attention owing to their unique electronic structures and tunable surface chemistry. In this study, the adsorption and sensing characteristics of toxic gas molecules on monolayer α‐antimony nitride (α‐SbN), a representative 2D V–V material, were systematically investigated by combining first‐principles density functional theory (DFT) and non‐equilibrium Green's function (NEGF) calculations. Among all studied gases, α‐SbN exhibits the strongest interaction with NO 2 , with an adsorption energy of −0.729 eV, indicating a stable yet reversible physisorption process dominated by van der Waals interactions. The adsorption of NO 2 induces significant modifications in the band structure and charge distribution of α‐SbN, leading to the formation of impurity states and a noticeable reduction in the band gap. At a bias voltage of 2.7 V, the NO 2 adsorption system exhibits a more pronounced increase to 26.52 µA, corresponding to an enhancement of approximately 72% relative to the pristine monolayer, demonstrating a remarkable enhancement in conductivity and sensing response. These combined features with strong sensitivity, excellent selectivity, and reversible adsorption, highlight monolayer α‐SbN as a high‐performance 2D material for NO 2 sensing applications.