Properties of a weakly ionized NO gas sensor based on multi-walled carbon nanotubes

Jingyuan Zhang, Yong Zhang, Zhigang Pan, Shuang Yang, Jinghui Shi, Shengtao Li, Daomin Min, Xin Li, Xiaohua Wang, Dingxin Liu, Aijun Yang

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Abstract

Nitric oxide NO is one of the major targets for environmental monitoring, but the existing NO sensors are limited by their low sensitivity and narrow test range. Here, a NO gas sensor employing multiwalled carbon nanotubes (MWCNTs) was fabricated, and its properties in NO-N2 mixture were investigated from both emission and ionization. The current Ie passing through the nanotubes cathode was found to decrease with increasing NO concentration and increase linearly in different slopes with the extracting voltage Ue. It is shown that the Schottky barrier of the MWCNTs calculated by Ie increased with NO concentration due to the adsorption of NO gas, which restrained the electron emission and consequently weakened the ionization. The positive ion currents Ic passing through the collecting electrode at different voltages of Ue were found to monotonically decrease with increasing NO concentration, which was induced by both of the reduced electron emission and the consumption of the two excited metastable states N2(A3Σu+) and N2(a′1Σu-) by NO. The sensor exhibited high sensitivity at the low temperature of 30°C. The calculated conductivity was found to be able to take place of Ic for NO detection in a wide voltage range of 80-150 V Ue.

Original languageEnglish
Article number093104
JournalApplied Physics Letters
Volume107
Issue number9
DOIs
Publication statusPublished - 2015 Aug 31
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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  • Cite this

    Zhang, J., Zhang, Y., Pan, Z., Yang, S., Shi, J., Li, S., Min, D., Li, X., Wang, X., Liu, D., & Yang, A. (2015). Properties of a weakly ionized NO gas sensor based on multi-walled carbon nanotubes. Applied Physics Letters, 107(9), [093104]. https://doi.org/10.1063/1.4930020