Research Of ZnO Doping And Its Multilayer Structure

In the past decades, research based on the ZnO has been penetrated into various fields. So far, the studies of ZnO material focus on ZnO doping and impurity defects, ZnO nanostructures, optoelectronic devices based on ZnO, transparent conductive thin films as well as the growth of ZnO single crystal film. On the basis of existing studies, this dissertation conducted further study on several hot topics, including p-type ZnO doping, ZnO fluorescence enhancement and transparent conductive film based on the ZnO nanostructures.Ag-S codoped p-type ZnO films were fabricated on the quartz by e-beam evaporation method using Ag2O and ZnS as the dopant. Effects of oxygen concentration on the structure and optical properties of films were investigated. The prepared p-type ZnO films have characteristics of low resistivity and high hole concentration. The resistivity and the mobility have10-2Ω·cm and10-2cm2V-1s-1magnitudes, respectively, and the magnitude of hole concentration is1021～1022cm-3. The ZnO p-i-n homojunction consisting of a p-type layer (the prepared film), an n-type layer (1.0wt%Al-doped ZnO film) and an intrinsic layer (pure ZnO film) were also fabricated. The I-V curves show that the ZnO PN junctions have good rectification characteristic.Al/ZnO:Al thin films were grown by physical vapor deposition methods. The fluorescence enhancement of the structure has been investigated. ZnO:Al thin film covered with a metallic Al island film not only enhances the band edge fluorescence, but also generates a blue light emission peak located at around475nm. The band edge fluorescence and blue light emission can be enhanced4.5times and24times by introducing a5nm thickness Ta2O5insulating layer between Al island film and ZnO:Al film. The band edge fluorescence and blue light emission peak of Al/ZnO:Al thin film can be enhanced9times and83times, respectively, after300℃annealing treatment. According to the localized surface plasmon resonance theory, the scattering cross section and the absorption cross section of Al/ZnO:Al structure were calculated. The results well explain the fluorescence enhancement phenomenon observed from the experiments.Vertically aligned ZnO nanorod arrays on the ZnO:Al/Si substrates were successfully synthesized via a low temperature hydrothermal technique. Effects of growth temperature on structure and optical properties of ZnO nanorod arrays were investigated. The reflection value of ZnO nanorod arrays with growth temperature of120℃for normal incidence visible light is less than10%. It is lower than that of ZnO.Al seed layer (～20%). However, its transmittance for visible light is80%. The nanorod array has the characteristics of high transmittance and low reflectance.