The use of semiconducting metal oxides to develop highly sensitive CO gas sensors remains an important approach in the field of gas sensing applications. Zinc oxide (ZnO) as semiconducting metal oxide is considered as the promising resistive-type gas sensing material [1]. In this research, we describe the synthesis, characterization, and application of a very promising CO gas sensing material ZnO doped with different concentration of Ti and synthesized by magnetron sputtering [2] method. The structural, morphological and optical characteristics of the synthesized specimens were studied (Figure 1). Using a gas sensing measurement device, the CO sensing capabilities of different concentrations of Ti in ZnO structures were evaluated. The sensitivity, operating temperature, and response/recovery time were systematically investigated based on the change in electrical resistance of the materials in the presence of CO gas. Experimental results confirmed that 120W of Ti (DC) power of TZO showed a maximum (100 ppm) response to CO gas at 260°C operating temperature. The sensing mechanism of the TZO films with different concentration of Ti is discussed in detail. We believe that the Ti-doped, columnar ZnO nanostructure is a potential material for semiconductor-oxide-based CO gas sensors.

Figure 1. Ti doped ZnO films deposited by magnetron co-sputtering

Key words: CO gas sensor, magnetron sputtering, thin film, Ti-doped ZnO.

Acknowledgement

This research was supported by the research grant 021220FD2201 “Development of highly sensitive MOS based nano-film gas sensors” from Nazarbayev University.

Reference

[1] L. Zhu, W. Zeng, Room-temperature gas sensing of ZnO-based gas sensor: A review, Sensors Actuators, A Phys. 267 (2017) 242–261. https://doi.org/10.1016/j.sna.2017.10.021.

[2] H. Chen, J. Ding, F. Shi, Y. Li, W. Guo, Optical properties of Ti-doped ZnO films synthesized via magnetron sputtering, J. Alloys Compd. 534 (2012) 59–63. https://doi.org/10.1016/j.jallcom.2012.04.064.