Heterointerface-Induced Charge Transfer Kinetics in Sputtered MoTe₂-MoS₂ Nanocomposite for High-Performance Ambient...

The present research reports a nanostructured MoTe₂-MoS₂ n-n heterojunction-based gas sensor developed on a silicon (Si) substrate, demonstrating room-temperature (RT, 30 °C) nitrogen dioxide (NO₂) sensing. A controlled and one-step magnetron co-sputtering approach is utilized to deposit MoTe₂-MoS₂ nanocomposite thin film on a Si substrate, producing a uniform, dense, and porous nanoscale morphology. Herein, surface analysis and structural characterization of the MoTe₂-MoS₂/Si sensor reveal a rough and defect-rich morphology with abundant exposed edge sites, which significantly enhances the availability of active adsorption sites for effective gas sensing. The developed MoTe₂-MoS₂/Si heterostructured sensor delivers an exceptional sensor response of 74.4% with an ultrafast response/recovery time of 7.5/2 s toward 25 ppm of NO₂ at RT. Additionally, the present sensor showcases highly reproducible and consistent behavior over a wide range of NO₂ concentrations (1-60 ppm), along with remarkable selectivity against common potential interfering gases (H₂S, NH₃, CO, H₂) and a low detection limit of 700 ppb. This study provides critical insights into NO₂ sensing induced by heterointerface band modulation and defect-assisted adsorption at the sensor's surface, thereby providing a strong foundation for a reliable platform for high-performance NO₂ gas sensors based on the MoTe₂-MoS₂ heterostructure.