gamma-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 gamma-ray radiolysis. The surface of the networked SnO2 nanowires fabricated through the vapor-phase selective growth process was uniformly functionalized with the Au nanoparticles by the gamma-ray radiolysis process. Au nanoparticle-functionalized SnO2 nanowires were compared to bare SnO2 nanowires in terms of the NO2 sensing characteristics. Au functionalization sharply improved the sensitivity and response time of SnO2 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. (C) 2011 Elsevier B.V. All rights reserved.