Low-Temperature Growth of SnO2 Nanorod Arrays and Tunable n–p–n Sensing Response of a ZnO/SnO2 Heterojunction for Exclusive Hydrogen Sensors
✍ Scribed by Hui Huang; Hua Gong; Chee Lap Chow; Jun Guo; Timothy John White; Man Siu Tse; Ooi Kiang Tan
- Publisher
- John Wiley and Sons
- Year
- 2011
- Tongue
- English
- Weight
- 803 KB
- Volume
- 21
- Category
- Article
- ISSN
- 1616-301X
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✦ Synopsis
Abstract
Uniform SnO~2~ nanorod arrays have been deposited at low temperature by plasma‐enhanced chemical vapor deposition (PECVD). ZnO surface modification is used to improve the selectivity of the SnO~2~ nanorod sensor to H~2~ gas. The ZnO‐modified SnO~2~ nanorod sensor shows a normal n‐type response to 100 ppm CO, NH~3~, and CH~4~ reducing gas whereas it exhibits concentration‐dependent n–p–n transitions for its sensing response to H~2~ gas. This abnormal sensing behavior can be explained by the formation of n‐ZnO/p‐Zn‐O‐Sn/n‐SnO~2~ heterojunction structures. The gas sensors can be used in highly selective H~2~ sensing and this study also opens up a general approach for tailoring the selectivity of gas sensors by surface modification.