Inorganic gas sensing performance of χ3-borophene and the van der Waals heterostructure

Recently, two-dimensional (2D) material chi(3)-borophene has been synthesized in experiment. Combining density functional theory with non-equilibrium Green's function method, in the present work we theoretically investi-gated the adsorption behaviors of small gas molecules NO, NO2, NH3, CO and CO2 on chi(3)-borophene, and cor-responding transport properties and sensing performance. Our results suggest that NO, NO2, NH3 and CO adsorb on this 2D material by chemical adsorption, while CO2 adopts physical adsorption. The transport properties of chi(3)- borophene are sensitive to the adsorption of NO, NO2, NH3 and CO, thus it can be used to construct gas sensor for these gas molecules. Especially, chi(3)-borophene is very sensitive to NO and, more interestingly, the sensing per-formance for NO can be greatly improved by applying in-plane strain. In addition, using semiconductor WSe2 as the substrate, we theoretically predicted a kind of van der Waals heterostructure. It is found that, although the adsorption behaviors of NO, NO2, NH3 and CO on chi(3)-borophene are hardly affected by the substrate, WSe2 can effectively enhance the stability of chi(3)-borophene and positively modulate the sensing performance, suggesting an actual way to realize chi(3)-borophene gas sensor.