Enhanced ethanol gas sensing performance of the networked Fe₂O₃-functionalized ZnO nanowire sensor

ZnO nanowires functionalized with Fe₂O₃ nanoparticles were synthesized by a two-step process consisting of the thermal evaporation of a mixture of ZnO and graphite powders in an oxidizing atmosphere and solvothermal deposition of Fe₂O₃ and their ethanol gas sensing properties were examined. The diameters and lengths of the Fe₂O₃-functionalized ZnO nanowires were 50-200 nm and 10-30 μm, respectively. The diameters of the nanoparticles Fe₂O₃ ranged from 10-30 nm. The Fe₂O₃-functionalized ZnO nanowire sensor showed significantly stronger response to ethanol gas than the pristine ZnO nanowire counterpart. The former also showed more rapid response than the latter. Both the pristine and Fe₂O₃-functionalized ZnO nanowire sensors showed the strongest response to ethanol gas at 200 °C. The enhanced sensing performance of the Fe₂O₃-functionalized ZnO nanowire sensor towards ethanol gas is due to a combination of the modulation of the interface potential barrier and the depletion layer width, the catalytic activity of Fe₂O₃ for ethanol oxidation and the creation of active adsorption sites by incorporation of Fe₂O₃.