Wide-range ethanol sensor based on a spray-deposited nanostructured ZnO and Sn–doped ZnO films

• Published in: Sensors and actuators. A. Physical. 2024-05, Vol.370, p.115213, Article 115213
• Main Authors: Chaudhary, Dinesh Kumar, Acharya, Tirtha Raj, Shrestha, Rajesh, Gautam, Sandhya, Shrestha, Pitamber, Dhakal, Agni, Shrestha, Shankar Prasad, Al-Khedhairy, Abdulaziz A., Wahab, Rizwan, Choi, Eun Ha, Kaushik, Nagendra Kumar, Joshi, Leela Pradhan
• Format: Article
• Language: English
• Subjects: Ethanol sensing; Film resistance; Gas response; Sn–ZnO film; Spray pyrolysis
• ISSN: 0924-4247; 1873-3069
• DOI: 10.1016/j.sna.2024.115213

This study compares the performance of a highly sensitive ethanol sensor incorporating a zinc oxide (ZnO) nanostructured film with that of (1–3) % tin-doped zinc oxide (Sn–ZnO) nanostructured films across a wide range of ethanol concentrations from 0.5 to 400 ppm. X-ray diffraction analysis confirms the polycrystalline structure of Sn–ZnO films, with a significant (002) plane orientation. Notably, Sn doping reduces the optical bandgap from 3.28 eV (ZnO) to 2.41 eV (3% Sn–ZnO). Ethanol vapor sensing experiments reveal that the 2% Sn–ZnO film operates at a lower temperature of 220 °C compared to the ZnO film (290 °C). Particularly, the 2% Sn–ZnO film exhibits rapid and strong responses to low ethanol concentrations (0.5–100 ppm) at this temperature. Response values of 2.22 ± 0.01 and 17.66 ± 0.08 with response times of 11 ± 1 and 15 ± 1 s are achieved at ethanol concentrations of 0.5 and 400 ppm, respectively. Conversely, the ZnO film performs better at higher ethanol concentrations (150–400 ppm). These findings advance gas sensing mechanisms in ZnO and Sn–ZnO films, with implications for future advancements in gas sensor technology. [Display omitted] •ZnO/ZnO–Sn thin film has a wide ethanol detection range of 0.5–400 ppm.•Sn doping of ZnO changes thin film properties for ethanol sensing.•2% ZnO–Sn thin film produces a strong response to 100 ppm ethanol.•2% ZnO–Sn thin film exhibits a fast response to 0.5–400 ppm ethanol.