Self-heated CO gas sensor based on Au-decorated Sb-implanted WS2 nanosheets

In this study, Sb ions were implanted into p-type tungsten disulfide (WS2) nanosheets (NSs) at four different doses and carbon monoxide (CO) gas-sensing properties were investigated in the self-heating mode. The ratio of Sb5+ to Sb3+ was approximately 7:3, implying that Sb5+ ions were dominant and acted as donors to change the conductivity of WS2 to n-type. Implanting 2 × 1013 Sb ions/cm2 followed by annealing at 500 °C resulted in a sensor with the highest response to CO gas. Subsequently, the surface of the optimal gas sensor was decorated with Au nanoparticles (NPs), leading to its improved response to CO gas. The main parameters related to the enhanced gas performance of the optimized gas sensor were the increase in O ionosorption with generation of S vacancies, formation of Au/Sb–WS2 heterojunctions, and catalytic and spillover effects of Au NPs. The possibility of realizing a self-heated, CO-gas-sensitive sensor using decorating Sb-implanted WS2 NSs with Au was demonstrated.