Design And Simulation Of Gas Sensor Device Based On Two-dimensional CuSbX₂ (X=S,Se) Material

Two-dimensional(2D)materials hold great promise in future nanodevice applications due to their high mobility,outstanding mechanical performance,and large surface-to-volume ratio,as demonstrated in extensive studies of graphene,black phosphorus,and transition-metal dichalcogenides.The utility of these materials,however,is limited by intrinsic shortcomings,such as the lack of a band gap in graphene,the fast degradation of black phosphorus in ambient conditions and the relatively low mobility of MoS2 due to the inherent sulfur vacancies.Therefore,continuing work has motivated in search of more 2D materials exhibiting excellent properties that lead to specific improved performance.CuSbS2 is a ternary transition metal chalcogenide which has been experimentally synthesized and which has a layered structure similar to a binary transition metal chalcogenide.The electrical properties of the two-dimensional CuSbS2 monolayer were studied by density functional theory.The calculation results show that CuSbS2 monolayer is a semiconductor material with a direct band gap of 1.1 eV,which has carrier mobility very close to that of the MoS2 monolayer,and it can well capture visible light,infrared light,and ultraviolet light.In particular,we studied the adsorption behavior of gas molecules on a two-dimensional CuSbS2 monolayer by combining density functional theory calculations with non-equilibrium Green’s function methods.The relative current change achieves 1968%at 0.05 V and 77%at 0.25 V for the CuSbS2 monolayer with NO2 and SO2 adsorption,respectively,implying that monolayer CuSbS2 is highly sensitive to SO2 and NO2 molecule.Our results indicate that CuSbS2 monolayer is a potential candidate in the application of efficient gas sensors.In addition,the electrical properties of the two-dimensional CuSbSe2 monolayer and the response to gas adsorption were studied on the basis of density functional theory.Different from the two-dimensional CuSbS2 monolayer,the CuSbSe2 monolayer is a semiconductor material having an almost direct band gap of about 0.9 eV.The CuSbSe2 monolayer has high carrier mobility and light absorption properties.At the same time,the sensing performance of CuSbSe2 monolayer was studied by the combination of DFT and NEGF.The CuSbSe2 monolayer has high sensitivity and selectivity to the adsorption of SO2 and NO2 molecules and can be applied in the field of gas capture and sensing.