Sensors for inorganic vapor detection based on carbon nanotubes and poly(o-anisidine) nanocomposite material

A gas sensor, fabricated by selective growth of aligned carbon nanotubes (CNTs) by pulsed plasma on Si3N4/Si substrates patterned by metallic platinum, is presented for inorganic vapor detection at room temperature. Poly(o-anisidine) (POAS) deposition onto the CNTs device was shown to impart higher sensitivity to the sensor. Upon exposure to HCl the variation of the CNTs sensitivity is less than 4%, while the POAS-coated CNTs devices offer a higher sensitivity (i.e. 28%). The extended detection capability to inorganic vapors is attributed to direct charge transfer with electron hopping effects on intertube conductivity through physically adsorbed POAS between CNTs.