Room-temperature NH_3 Gas Sensing Property of VO_2(B)/ZnO Hierarchical Heterogeneous Composite with Nanorod Structure
LIANG Ji-Ran;ZHANG Ye;YANG Ran;ZHAO Yi-Rui;GUO Jin-Bang;School of Microelectronics, Tianjin University;
VO_2(B)/Zn O nanorods hierarchical heterogeneous composite was synthesized by solution growth method on VO_2(B)nanorods surface.Effects of Zn O seeds’solution concentration on microstructure and NH_3 gas sensing properties of composite structures were investigated.X-ray diffractometer and scanning electron microscopy were used to characterize the crystal structure and surface morphology of the samples.NH_3 gas sensing properties of the composite was measured by the gas testing system at different temperatures and gas concentrations.The results show that Zn O grows on VO_2(B)surface and changes its shape from nanoparticle to nanorod as the Zn O seeds’solution concentration increasing from 0.002 mol/L to 0.03 mol/L.ZnO nanorods radially grows on the VO_2(B)nanorod surface and branch-shaped hierarchical heterogeneous VO_2(B)/ZnO composite structures are formed when the solution concentration is 0.01 mol/L.The composite exhibits high gas response and outstanding selectivity at room temperature.The response value reaches 5.6 while the response time is reduced to 2 s at room temperature.This excellent NH_3 gas sensing performance is related to the highly dense VO_2(B)/ZnO hetero-junction and hierarchical structure.The present results may provide more information for design and fabrication of low power and high sensitive NH_3 gas sensors at room temperature.
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