Studies on sputtered deposited MoS₂ thin films for efficient nitrogen dioxide (NO₂) sensor

In the present work, we report the controlled synthesis of Cu-functionalized MoS₂ nanoworm thin films-based NO₂ sensors utilizing the reactive co-sputtering technique. X-ray photoelectron spectroscopy and photoluminescence spectroscopy were used to study the surface chemistry and defects of as-prepared samples. Additionally, UV-Visible spectroscopy provided new insights into the absorbance and band gap studies. The sensing capabilities of pure MoS₂ and Cu-MoS₂ thin films were investigated for nitrogen dioxide (NO₂) gas concentrations (2-200 ppm) at the optimal working temperature of 100°C. The Cu-MoS₂ sensor provides a high sensing response as compared to the pure MoS₂ thin-film sensor towards 20 ppm of NO₂ gas with a fast response and recovery time. The Cu-MoS₂ thin-film sensor is highly sensitive, stable, and selective towards NO₂ against NH₃, CO, and H₂ gases. The developed 2D MoS₂ thin film-based sensor is observed to be extremely suitable in terms of LOD (2ppm), accuracy, stability, wide target gas range (2-200 ppm), low operating temperature (100°C), and selectivity towards NO₂ gas. As a result, it might be a novel way to create a chip sensor for the accurate detection of NO₂ in the environment.