DEVELOPMENT OF MULTI WALLED CARBON NANOTUBES GAS SENSOR BASED ON IONIZATION

Multiwalled carbon nanotubes (MWCNT) have started to be developed as the
sensing element for the ionization-based gas sensors due to the demand for improved
sensitivity, selectivity. stability and other sensing properties beyond what can be
ot1ered by the conventional ones. Although these limitations have been overcome. the
problems still remain with the conventional ionization-based gas sensors in that they
are bulky and have large breakdown voltage and high temperature such that they are
not safe for operation. Nanostructured electrode in the form of aligned MWCNT array
with uniform nanotips can enhance the electric field significantly even at a low
applied voltage. The objective is to develop novel gas sensor with enhanced sensing
properties by growing specific MWCNT and integrating this sensing element in an
ionization contiguration. Aligned MWCNT arrays were grown in thermal and floating
catalyst chemical vapor deposition (CVD) system.