Effect of laser irradiation on carbon nanotube films for NOx gas sensor

A carbon nanotube (CNT) thin film prepared by the thermal CVD method was flashed by second harmonic light of a pulsed Nd:YAG laser (λ = 532 nm) under various laser fluences. A part of the defective CNTs and amorphous carbon in the film was removed by 10 shots of laser irradiation at Ef = 600 mJ/cm2. Raman spectra of the laser irradiated CNT thin film showed the increase of IG/ID ratio, which indicated that the CNTs thin film was purified by laser irradiation. A multi-walled CNTs (MWCNTs) based gas sensor treated by laser irradiation showed good sensor response to NO gas.