A Carbon Nanotube Based Ionization Sensor Array to Gas Mixture

Abstract

The three kinds of gases such as NO 2 , NO, and SO 2 produced by industrial combustion process are the main sources of atmospheric pollution. Almost all the available technologies of measuring three components in mixed gases are limited by detection range, operating temperature, and integration, etc. Here we report an array with three triple-electrode carbon nanotube sensors and its sensitivity to the three flue gas components. The three sensors operate at the same gas ionization mechanism and are comprised of a common long cathode, three extracting electrodes and three collecting electrodes, and are set by different electrode separations with $75 \boldsymbol{\mu} \mathbf{m}, 100 \boldsymbol{\mu} \mathbf{m}$ , and $120 \boldsymbol{\mu} \mathbf{m}$ , respectively. We explored and obtained distinct single-valued sensitive characteristics to the three-component gases at given voltages applied on electrodes, which should be higher than a critical voltage to obtain single-valued sensitivities of the three sensors. The standard deviation of repeatability experiment is less than 0.133 nA, which indicates that the sensor has a good repeatability. The array displays a high level of integration and small size, and also has the potential to detect the concentrations of different components of gas mixtures.