Doping strategy of BSe/WSe2 heterostructures to realize the adsorption and sensing of harmful NH3 and NO2 gas molecules: a density functional theory study

In the present study, density functional theory calculations were used to examine different stacking configurations of BSe/WSe 2 van der Waals heterostructures. Then, the binding of noble metals (Ag, Au, Pd and Pt) on the surface of heterostructures was investigated. Adsorption behaviors of NH 3 and NO 2 molecules on the considered Ag modified BSe/WSe 2 heterostructures was also explored. The lattice mismatch rate is calculated to be 1.22%, which is lower than the threshold value, indicating the feasibility of BSe/WSe 2 heterostructure formation. The binding energy of Ag atom on the hollow site of BSe/WSe 2 substrate is determined to be -1.35 eV, implying the stability of Ag modified material for gas adsorption. However, the highest binding strength belongs to the Pt adsorption on the hollow position with significant binding energy of -2.25 eV. The band structures, charge density difference, recovery time and work functions were also analyzed for the adsorption systems. Both NH 3 and NO 2 molecules are chemisorbed on the Ag modified BSe/WSe 2 heterostructure. Among the adsorption configurations, NO 2 adsorption by double O atoms exhibits the large adsorption energy of -2.04 eV, revealing the strong interaction between gas molecule and substrate. The results suggest that the Ag modified BSe/WSe 2 heterostructure has a great potential for application as effective gas sensor.