Improved recovery of NO2 sensors using heterojunctions between transition metal dichalcogenides and ZnO nanoparticles

The stable recovery of gas sensors is an important indicator for evaluating their performance. Hitherto, the use of external light sources and/or an increase in the operating temperature has been effective in improving the recovery rate of gas sensors. Herein, heterojunctions were formed between the two-dimensional transition metal dichalcogenide nanosheets and zero-dimensional ZnO nanoparticles to improve the recovery rate of a NO₂ sensor. Scanning electron microscopy and Raman spectroscopy suggested a successful deposition of ZnO nanoparticles onto the MoS₂ and WSe₂ nanosheets. The sensing response to 10 ppm NO₂ gas at 100 °C indicated that the heterojunction formed by ZnO and MoS₂ or WSe₂ successfully improved the recovery rate of the sensor by 11.87% and 19.44%, respectively, whereas the sensitivity remained constant. The proposed approach contributes to improving the performance of gas sensors.