Publication details
Plasma Processing and ALD Modification of Multi-walled Carbon Nanotubes for Ammonia Gas Sensing
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| Year of publication | 2018 |
| Type | Appeared in Conference without Proceedings |
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| Citation | |
| Description | Carbon nanotube (CNTs)-metal oxide semiconductor (MOS) hybrid nanostructures can provide a new pathway for room temperature chemiresistive gas sensors due to combined properties of both the materials and the creation of heterojunctions between CNTs and MOS. Multi-walled carbon nanotubes (MWCNTs) were grown on Si substrates coated with SiO2 layer by catalytic chemical vapor deposition (CCVD) and coated by TiO2 films of different nominal thicknesses, 5, 10 and 20 nm, using atomic layer deposition (ALD). ALD is a self-limiting surface process providing highly uniform and conformal coatings if the surface reactive sites exist. CNT surface is quite inert and therefore, a modification of MWCNTs by carboxyl plasma polymer (PP) film prior to ALD of TiO2 was also applied. The thinnest TiO2 film formed island-like structure but the carboxyl PPs improved the film uniformity as observed by transmission electron microscopy. Raman spectroscopy revealed increased structural disorder of sp2 carbon when coated by TiO2 or carboxyl PP. The highest sensor response to NH3 was obtained for the thinnest TiO2 film and the sensors coated with carboxyl PP/TiO2 double layer showed higher response as compared to the pristine CNTs and those without the carboxyl PP film. |
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