Electrical properties of aligned carbon nanotubes for gas sensing applications under ambient conditions

Keywords:
multi walled carbon nano tubes, gas sensors, ambient conditions, sensitivity

Abstract:
New hybrid multi walled carbon nano tubes (MWCNTs) for He, NH3, Ar and H2 gas sensing was developed using MWCNTs into a SiO2 as substrates. The fabrication process was done by heat-treatment of the MWCNTs/SiO2 layer by spin coating using an organometallic solution dispersed with MWCNTs. The hybrid sensors were utilized to detect He, NH3, Ar and H2 concentrations in flowing air or N2, by considering alterations in electrical properties. All the studies were conducted at room temperature. Hybrid sensors with varying concentrations of MWCNTs were also examined to elucidate the effect of a concentration of MWCNTs on the sensing properties of the sensors. The results from ionization experiments show that helium displays the lowest (183V) and ammonia shows the highest (457V) breakdown voltage. A SiO2 sensor without MWCNTs, a blank sample, was also examined for comparative studies. Comparative gas sensing results have elucidated that the prepared hybrid MWCNTs/SiO2 sensors exhibit much higher sensing sensitivity and recovery properties in detecting the gases under ambient conditions in comparison to the blank SiO2 sensor. The gas ionization mechanism has proven to display novel performance through ambient condition and low break down voltage respectively.
 
Keywords: Multi walled carbon nano tubes, Gas sensors, Ambient conditions, Sensitivity

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Nanotech 2006 Conference Program Abstract