Methane sensing properties of platinum catalysed nano porous zinc oxide thin films derived by electrochemical anodization

作者：Basu P K; Bhattacharyya P; Saha N; Saha H; Basu S^*

来源：Sensor Letters, 2008, 6(1): 219-225.

DOI：10.1166/sl.2008.024

• nanoporous ZnO
• photoelectrochemical method
• methane sensing
• MIM
• platinum contact

The nanoporous ZnO thin film was prepared by anodic oxidation of high purity Zn sheet in absence and in presence of UV radiation and a methane gas sensor was fabricated using an interesting metal-insulator-metal (MIM) device configuration, Pt/ZnO/Zn. The undoped ZnO film deposited in presence of UV radiation showed superior material properties and improved gas sensing characteristics for methane. The V-I characteristics of the sensor device were recorded in absence and in presence of low concentrations of methane at different temperatures. The response, its variations with temperature and the time of response were calculated. With platinum as catalytic contact the response of the order of 0.78 +/- 5% and the time of response of 12 +/- 0.5% sec were obtained with 1% methane in nitrogen carrier gas at an optimum temperature of 240 degrees C. The performance of the sensor in presence of 1% methane in synthetic air was also studied and a decrease in the response was observed. The sensor was also tested with 1% hydrogen in nitrogen and a selectivity for methane was obtained at higher temperature. A cursory stability study of the sensor was carried out and a stable operation for about 16 hours could be achieved. A possible mechanism for methane sensing was proposed to understand the response characteristics of the ZnO-based MIM device for gas sensors.

• 出版日期2008-2