Fabrication of sensitive SWCNT sensor for trace level detection of reducing and oxidizing gases (NH3 and NO2) at room temperature

In the present work, rare dense and long network of single wall carbon nanotubes (SWCNTs) were successfully grown on Fe (Iron) based catalyst Si (Silicon) substrate through Plasma enhanced chemical vapour deposition (PECVD) technique at an operating temperature of 650 °C. The catalyst has been deposited by RF-Sputtering technique. The acetylene (C₂H₂) was used as the carbon source gas. The surface morphology and structural characterization of as grown SWCNTs have been properly done by various techniques like FESEM, HRTEM, and Raman Spectroscopy. From as grown SWCNTs, highly sensitive SWCNT sensor was fabricated for the trace level detection of NH₃ and NO₂ at room temperature. Different sensor characteristics like sensor response, repeatability, stability, resistance variation and selectivity of the as fabricated SWCNT sensor were investigated properly for both the gases (NH₃ and NO₂) and it was found that all the characteristics are in good agreement with reported work. In addition of this, the effect of operating temperature on sensor response was also conducted and it was found that sensitivity decreases with increasing temperature because desorption enhances with increasing temperature. Quick sensor response/recovery characteristics were obtained from the fabricated sensor and is a step forward towards security reasons in various sectors.