Room-temperature high-sensitivity H2S gas sensor based on dendritic ZnO nanostructures with macroscale in appearance

Single-crystal dendritic ZnO nanostructures in appearance of macroscale in mass production have been synthesized via the vapor-phase transport method with Cu catalyst at 930 degrees C. The hierarchical ZnO dendrites with a long central trunk and lots of multilevel branches are composed of well-oriented nanorods whose diameters range from 60 to 800 nm. Gas sensors based on as-synthesized ZnO products exhibit high sensitivity and selectivity to H2S gas at room temperature through detecting various gases. The large modulation of the energy barrier of contact between nanorods in ZnO dendrites by H2S gas at room temperature might be the origin of the high sensitivity. The results demonstrate that the ZnO dendrites, with macroscopical appearance and properties of nanomaterials, are potential to develop effective and high performance gas sensors. Moreover, the detailed humidity characteristics of the sensor have also been investigated in the relative humidity range of 5%-97.6%. (c) 2008 American Institute of Physics.