Au-Loaded WS₂/SnO₂ Heterostructure for Room Temperature Detection of CO at ppb-Level

There is a growing demand for gas sensors with excellent efficiency, high flexibility, and low energy consumption due to the rapid development of smart electronic devices. Metal-oxide–semiconductor (MOS) nanostructures have been the preferred choice for advanced gas sensors over the last 30 years. However, MOS sensors suffer from drawbacks, such as low selectivity, high operating temperatures, high power consumption, and stability issues. To find the alternative way, this work focuses on the modeling and simulation of a low power gas sensor based on Au-loaded WS2/SnO2 heterostructure using the COMSOL Multiphysics platform. Under optimized conditions, the Au-loaded WS2/SnO2 heterostructure can detect carbon monoxide (CO) with high sensitivity even at a low concentration of 25 parts per billion (ppb) at room temperature (RT). Moreover, the sensor shows a wide detection range of 25 ppb–150 parts per million (ppm) under exposure of CO. The Au-loaded WS2/SnO2 heterostructure also exhibited high selectivity toward CO against a variety of interference gases, including methane (CH4), nitrogen dioxide (NO2), benzene (C6H6), sulfur dioxide (SO2), hydrogen sulfide (H2S), carbon dioxide (CO2), and ethanol (C2H6O). The obtained sensing performance can be attributed to the charge transfer mechanism in the WS2/SnO2 heterostructure along with the catalytic effect of Au. Thus, this research could be useful to fabricate real gas sensors for practical applications.