Research On Conductivity Property Of Nano ZnO Sensing Device

ZnO has many excellent characteristics as a wide band gap semiconductor material. It is widely used in many fields such as nanogenerator, UV detector, pressure sensitive sensor, memory and so on. Single crystal ZnO nanobelt s with high crystal quality and specific surface have excellent electrical properties, which are the main component of nano devices. Almost all the related publi cations focused on the current –voltage(I–V) characteristics of semiconductor nanostructures instead of the mechanism of the length dependence. Study on the basic conductive property of single crystal semiconductor nanobelts can help to improve the performance of nano devices.In this thesis, the ZnO nanobelts was synthesized by chemical vapor deposition method. The main advantage of this method is that the preparation of high crystalline ZnO nanobelt is convenient for experimental study. The characterization of ZnO nanobelt show that ZnO nanbelts have good banded structure, smooth surface, uniform size. By electron diffraction analysis, it is confirmed that the ZnO nanobelts were wurtzite structure, and the growth direction was [0110].To study the relationship between resistance and length, we first mounted the ZnO nanobelt on an intrinsic silicon wafer with silver paste, which was coated with a thin layer of silicon oxide. Then use the Pt coated conductive AFM to scan the ZnO nanobelt in order to form the current voltage measurement circuit. The conductive properties of the ZnO nanobelt were finally determined by experiments. Aim at the electrical properties of ZnO nanobelts, we analyzed the electrical conductivity of isotropic and anisotropic materials respectively by using the finite element method. Analyzed the distribution of current density as the favorite conducting planes and the growth direction were in the same direction. Finally, we studied the properties of ZnO varistor doped with Bi2O3 and Co2O3, and compared the performance parameters of the samples with different doping content under the same conditions.In this thesis, we not only study the special electrical conduction mechanism, but also provide the basis for improving the function of the nano devices, and lay a solid foundation for the development of the new generation of high-performance nano devices in the future.