Strain-engineered black arsenene as a promising gas sensor for detecting SO₂ among SF₆ decompositions

The adsorption and gas sensing properties of black arsenene (B-As) regarding sulfur hexafluoride (SF₆) and its six decompositions (SOF₂, SO₂F₂, SO₂, H₂S, HF, and CF₄) are investigated using density functional theory combined with the nonequilibrium Green's function. The sensitivity of B-As is evaluated by considering the most stable adsorption configuration, adsorption energy, work function, recovery time, local density of states, and charge transfer between the gas molecules and B-As. It is demonstrated that B-As is more sensitive to the SO₂ molecule than to the other decompositions. Additionally, the adsorption strength can be manipulated by controlling the external electric field (E-field). The application of tensile biaxial strain results in more isotropic electrical conductance of B-As, and it can also effectively enhance the response toward SO₂. For example, under a 1% equibiaxial tensile strain, a 132% response can be obtained along the zigzag direction. This work suggests the promising prospects of B-As-based gas sensors for detecting SO₂ among SF₆ decompositions. (paper)