Significant enhancement of the NO2 sensing capability in networked SnO2 nanowires by Au nanoparticles synthesized via γ-ray radiolysis.

γ-Ray radiolysis was applied to the synthesis of Au nanoparticles. The growth behavior of Au nanoparticles was systematically investigated as a function of the processing parameters under γ-ray radiolysis. The surface of the networked SnO(2) nanowires fabricated through the vapor-phase selective growth process was uniformly functionalized with the Au nanoparticles by the γ-ray radiolysis process. Au nanoparticle-functionalized SnO(2) nanowires were compared to bare SnO(2) nanowires in terms of the NO(2) sensing characteristics. Au functionalization sharply improved the sensitivity and response time of SnO(2) nanowire-based gas sensors, most likely due to the spillover and the catalytic effects of Au nanoparticles. The methodology used in this work can be easily extended to synthesize various combinations of metal nanoparticles and oxide nanowires, which may be useful materials for use in detecting hazardous substances.