Performance improvement of MOCVD grown ZnGa2O4 based NO gas sensors using plasma surface treatment

• Published in: Applied surface science 2023-11, Vol.637, p.157929, Article 157929
• Main Authors: Chang, Ting-Yu, Kumar Singh, Anoop, Shao, Jhih-Hong, Huang, Chiung-Yi, Shieh, Jia-Min, Wuu, Dong-Sing, Liu, Po-Liang, Horng, Ray-Hua
• Format: Article
• Language: English
• Subjects: Gas sensor; Nitric oxide; Plasma treatment; Surface morphology; ZnGa2O4 epilayer
• ISSN: 0169-4332
• DOI: 10.1016/j.apsusc.2023.157929

[Display omitted] •ZnGa2O4 has shown promising results as a material for NO gas sensing applications.•Plasma surface treatment improves the performance of ZnGa2O4 based NO gas sensors.•The limit of detection is found to be 2.4 ppb.•ZnGa2O4 gas sensor possess highly selectivity for NO gas.•Ar surface modification techniques can enhance the performance of gas sensors. Gas sensors are essential devices in various industrial and environmental monitoring applications. Nitric oxide (NO) is a harmful gas that is produced in various combustion processes and is associated with air pollution and respiratory diseases. Zinc gallate (ZnGa2O4) has shown promising results as a material for NO gas sensing applications. Previously, the performance of NO gas sensors based on ZnGa2O4 epilayers was not substantial. However, there is potential for further improvement by optimizing their surface properties. Plasma surface treatment has been widely utilized to modify the surface characteristics of materials, including semiconductors, for various applications. We have investigated the impact of plasma surface treatment on the performance of metal–organic chemical vapor deposition grown ZnGa2O4 based NO gas sensors in this work. An inductive coupled plasma reactive ion etching was used to apply Ar plasma to successfully optimize the sensing response of the ZnGa2O4 based gas sensor for NO gas. The sensor response for ZnGa2O4-based NO gas sensors is 159.5%, which is enhanced by 8 times and reached 1276.1% under 5 ppm NO gas concentration after 10 min Ar plasma treatment. The limit of detection is found to be 2.4 ppb. These results demonstrate that Ar plasma treatment significantly improved the ZnGa2O4-based NO gas sensor’s response. The cross-selectivity of this sensor is tested among NO, CO2, CO, and SO2 gases, which indicated that ZnGa2O4 gas sensor possess highly selectivity towards NO gas. This study provides valuable insights into the surface modification techniques for enhancing the performance of gas sensors, which can have a significant impact on the development of advanced sensing technologies for environmental and industrial applications.