Enhanced Gas-Sensing Properties of Au-Loaded ZnO/WSe2 Heterostructure at Room Temperature-Modeling and Simulation

Two-dimensional transition metal dichalcogenide (TMD)-based heterostructure devices have gained significant interest for detecting various gases because of enhanced sensitivity, selectivity, stability, and complete recoverability. However, a better understanding of the sensing properties of these heterostructures is still required. This study focuses on the modeling and simulation of Au-loaded ZnO/WSe2 heterostructure using the finite element method in COMSOL Multiphysics. Under optimized conditions, the Au-loaded ZnO/WSe2 heterostructure exhibited outstanding sensing properties toward NH3 at room temperature (RT) with superior sensitivity and fast response/recovery of 0.17728 ppm ${}^{-{1}}$ and 1.5/0.9 s, respectively. Moreover, the resulting heterostructure exhibited excellent selectivity to NH3 against a variety of interfering agents, including nitrogen dioxide (NO2), sulfur dioxide (SO2), ethanol (C2H6O), acetone [(CH3)2CO], formaldehyde (HCHO), benzene, and carbon monoxide (CO). Additionally, the sensor showed good stability at various humidity conditions, indicating potential for practical applications. The superior sensing properties can be attributed to the heterostructure’s quick electron transfer mechanism and Au’s catalytic effect, which lowers the activation energy, enhancing the sensor’s sensitivity. The developed sensor initiates a paradigm shift by opening the scope of detecting toxic gases at RT.