Nitric Oxide Gas Sensors Using Multilayered Thin Film with Interspaces

作者：Shimizu Akihiro; Morita Tsubasa; Yamaguchi Tomiharu^*; Hara Kazuhiro

来源：Sensors and Materials, 2018, 30(5): 1123-1132.

DOI：10.18494/SAM.2018.1836

• NO gas sensor
• WO3 thin film
• Ag catalyst
• interspace
• multiple-layered configuration

Nitric oxide (NO) is an air pollutant known to adversely affect the environment, humans, and other living organisms. Low-level NO gas is also created by human bodies and emitted as a component of exhaled breath and skin gas under some health conditions. Therefore, there is a strong demand for the monitoring of NO gas concentration. In this paper, we present novel NO gas sensors that have been developed using multilayered WO3-based thin films with interspaces. Ag doping into a WO3 thin film is effective in increasing the sensitivity to NO. Multilayered thin-film sensors with interspaces successfully enhance both sensitivity and selectivity to NO. The developed sensor with quadruple-layered sensing films can detect as low as 0.5 ppm NO gas with good selectivity at an operating temperature of 290 degrees C. The response and recovery times are 81 and 138 s, respectively, for the double-layered sensor, while its sensitivity is lower than that of the quadruple-layered sensor. Thus, the sensors are promising as a portable and inexpensive NO sensing device in various application fields such as environmental monitoring and health diagnosis.

• 出版日期2018