A novel SnO2 gas sensor doped with carbon nanotubes operating at room temperature

Abstract A new hybrid SWCNTs/SnO 2 gas sensor is developed by adding single-walled carbon nanotubes (SWCNTs) into a SnO 2 substrate. The fabrication involved heat-treating the SWCNTs/SnO 2 layer, which was fabricated by spin coating using an organometallic solution of dispersed with SWCNTs. The hybrid sensor is utilized to detect NO 2 concentrations in flowing air or N 2 , by considering alterations in electrical properties. The tests are performed at room temperature. Two hybrid sensors with different concentrations of SWCNTs are examined to elucidate the effect of a concentration of SWCNTs on the sensing properties of the sensors. A SnO 2 sensor without SWCNTs, a blank sample, is also examined for comparison. Comparative gas sensing results reveal that the prepared hybrid SWCNTs/SnO 2 sensors exhibit much higher sensing sensitivity and recovery property in detecting NO 2 gas at room temperature than the blank SnO 2 sensor. This finding shows that doping with SWCNTs improves the sensitivity of hybrid sensors. Microstructural observations revealed that SWCNT bundles are embedded in the SnO 2 matrix. Therefore, a model is presented to relate potential barriers to electronic conduction in the hybrid material. This model suggests that the high sensitivity is associated with the stretching of the depletion layers at the grain boundaries of SnO 2 and the SWCNTs/SnO 2 interfaces when detected gases are adsorbed.

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