Nano Archive

A novel highly sensitive gas ionization sensor for ammonia detection

Huang, Jiarui and Wang, Junhai and Gu, Cuiping and Yu, Kun and Meng, Fanli and Liu, Jinhuai (2009) A novel highly sensitive gas ionization sensor for ammonia detection. Sensors and Actuators A: Physical, 150 (2). 218 - 223.

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A novel highly sensitive gas ionization sensor for ammonia detection in ambient air is introduced in this paper. Carbon nanotubes (CNTs) grown on silicon substrate were incorporated to fabricate a gas ionization sensor. Application of a positive bias to the CNTs generates electric fields sufficiently to field-ionize passing gas-phase molecular and initiate a prebreakdown current. When the CNTs film is configured as the cathode, secondary electrons repelled away from the CNTs tips into the gap spacing make more ionizing collisions and also initiate a prebreakdown current. By monitoring the prebreakdown current, the gas ionization sensor was demonstrated to be capable of ionizing and detecting the ammonia and with a linear response over the entire range from 1 to 160 ppm ammonia in air. The sensitivity mechanism of the gas ionization sensor was also discussed in detail. The sensitivity and selectivity of the gas ionization sensor to the gases is not only dependent on its ionization energy but also its electric dipole moment. The novel CNTs-based gas ionization sensor described here exhibits high accuracy, repeatability and stability. The sensor is promising for use in various fields.

Item Type:Article
Uncontrolled Keywords:Ammonia; CNTs; Gas ionization sensor; Prebreakdown current
Subjects:Analytical Science > Nanotechnology for sensing and actuating
ID Code:4966
Deposited By:SPI
Deposited On:09 Apr 2009 11:50
Last Modified:09 Apr 2009 11:50

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