Synthesis and characterization of SWCNTs/ZnO hybrid nanocomposite for sensor applications

The present work focuses on the synthesis and characterization of single walled carbon nanotubes (SWCNTs)/Zinc oxide (ZnO) hybrid nanocomposite for resistive gas sensors. Both the materials, SWCNTs and ZnO are very well recognized for their individual gas sensing properties but synthesis of ZnO/SWCNT hybrid nanocomposites constitute a low cost solution for gas sensing devices with unique properties. In this research work, SWCNTs have been grown on Iron (Fe) deposited Silicon (Si) substrate and then decorated with ZnO nanoparticles to form hybrid nanocomposites structure. The as-grown SWCNTs and its nanocomposites were analyzed using field emission scanning electron microscope (FESEM), x-ray diffractometer (XRD), high resolution transmission electron microscope (HRTEM) and Raman spectroscopy. As synthesized nanocomposites were exposed with ammonia (NH₃) gas so that sensitivity of the gas can be recorded. The sensor response of as-grown SWCNTs and SWCNTs/ZnO sensor was measured to be 80%-100% and 150%-200% respectively, whereas SWCNTs/ZnO sensor response time is 4 - 5 s and recovery time is about 8-10 s, which is higher response time compared to as-grown SWCNT sensor.