We have investigated the fabrication of hydrogen gas sensors based on networks of Pd nanoparticles (NPs) deposited tin dioxide nanowires (NWs) SnO(2) NWs with tin NPs attached on the surface were obtained by a simple thermal evaporation of SnO crystalline powders The tin dioxide NWs were decorated with Pd NPs by the reduction process in Pd ion solution The sensors showed ultra high sensitivity (similar to 1 2 x 10(5)%) and fast response time (similar to 2 s) upon exposure to 10 000 ppm H(2) at room temperature These sensors were also found to enable a significant electrical conductance modulation upon exposure to extremely low concentrations (40 ppm) of H(2) in the air Our fabrication method of sensors combining with Pd NPs Sn NPs and n type semiconducting SnO(2) NWs allows optimized catalytic and depletion effect and results the production of highly sensitive H(2) sensors that exhibit a broad dynamic detection range, fast response times and an ultra low detection limit (C) 2010 Professor T Nejat Veziroglu Published by Elsevier Ltd All rights reserved