Electrode effects on gas sensing properties of nanocrystalline zinc oxide

• Published in: Nanostructured materials Vol. 10; no. 3; pp. 465 - 477
• Main Authors: Lin, Hong-Ming, Tzeng, Shah-Jye, Hsiau, Peng-Jan, Tsai, Wen-Li
• Format: Journal Article
• Language: English
• Published: Elsevier Science 01-04-1998
• ISSN: 0965-9773; 1872-9150
• DOI: 10.1016/S0965-9773(98)00087-7

Electrode effects on gas sensing properties have been examined by nanocrystalline zinc oxide sensor in this study. Nanocrystalline Zn is grown by the gas condensation method in a 5 mbar helium atmosphere on the surface of gold or silver electrodes and then undergoes step sintering to form nanocrystalline ZnO. The response of nanocrystalline ZnO in CO gas shows the decreasing of resistance that indicates a n-type metal oxide semiconductor behavior and in NO
2 gas shows a p-type metal oxide semiconductor effect that the resistance is increased with increasing NO
2 concentration. The response time of nanocrystalline ZnO sensor with Ag electrodes is fast in detecting NO
2 gas, but the sensitivity can not be recovered to the background after turning off the NO
2 gas. This result indicates that Ag electrodes are poisoned by NO
2 gas. The linear dynamic detecting range, response time, sensitivity and reliability of nanocrystalline ZnO sensor with Au electrodes is comparably good with that of nanocrystalline ZnO sensor with Ag electrodes.