Oxygen functionalisation of MWNT and their use as gas sensitive thick-film layers

Multi-wall carbon nanotubes (MWNT) were functionalised in an oxygen-based atmosphere by an inductively coupled RF-plasma at 13.56 MHz. X-ray photoelectron spectroscopy analysis showed that the chemical composition of the nanotube surface depends on the plasma conditions used. The MWNT were then deposited onto microhotplate gas sensor substrates by the drop coating method. A well-adhered thick-film of carbon nanotubes mesh (∼17 μm) was obtained after annealing in air. The influence of the different plasma conditions on the responsiveness of gas sensors fabricated with the functionalised MWNT was studied. The gas sensing properties were investigated both experimentally and theoretically for NO2, and NH3 at room temperature.