Fabrication of sensor based on MWCNT for NO2 and NH3 detection

MWCNT arrays fabricated by microwave plasma chemical vapor deposition on Si substrate with interdigital electrodes (IDE) were integrated into a resistive sensor design. A scanning electron microscope was used for the characterizations of MWCNTs. The gas response of MWCNT arrays to NH₃ and NO₂ gas were investigated at room temperature, respectively. The results exhibited that the thickness of MWCNT arrays controlled by growth time evidently affected gas sensing properties, and as-prepared MWCNT arrays presented low gas sensitivity to NH₃ and NO₂ gas, while the gas response can be significantly improved by anneal, which may be interpreted by the removal of by-products such as amorphous carbon or other functional groups on the MWCNTs surface.