Preparation And Properties Of Zinc Oxide Fluorescent Films In The Fed

Field emission display(FED) is a desirable display device because of its advantage of high brightness,broad angle of view,rapid response,wide range of working temperature and low power consumption.It demonstrates the superiority to the traditional cathode ray tube(CRT).There are two major factors determining the speed of FED's developing process: One is the designment and attainment of fine field emission arrays(FEAs) and another is the preparation of phosphor.Presently,although the improvement of FEAs is vast and fast,the studies and exploitation on appropriate phosphor developed very slowly. Therefore,the anode phosphor of FED must be provided with fine luminescent characteristics.Nowadays,the luminescent materials used in the industry still have lots of problems to solve to meet the need of production.It exists in the form of phosphor power and requires the complicated spraying craftwork when used in FED.If the phosphor material can be prepared in thin film type,it can be directly applied in FED as luminescent layer and then reduce the cost.Therefore,the luminescent thin film material has been the attention of researchers.In this paper,we select the ZnO thin film as the anode phosphor of our study object.According to the method of electrodeposition of ZnO thin film from an aqueous Zn(NO₃)₂ solution on indium tin Oxide(ITO)-covered glass substrate,we obtained high-quality luminescent thin film. The result of ZnO thin film which we get showed that through the electrodeposition a good kind of low-voltage driving cathode-luminescent phosphor was obtained and it has huge practical value in potential field emission display as phosphor material.The contents of the thesis research were following as:1. The experimental method of preparing ZnO thin film and the cross design experiment to optimize the depositing conditionsA simple electrobath system was used with ITO glass(prepared by CS-300 Magnetron Sputtering) substrate as the working electrode(or the cathode),zinc sheet (99.90% purity) as the active anode.The electrolyte was an aqueous solution composed of Zn(NO₃)₂.The experimental conditions including concentration of Zn(NO₃)₂,electronic current,deposition temperature and growth time were selected by the cross design experiment.2. The microstrucrure and surface morphology analysis of deposited ZnO thin filmThe ZnO thin film was electrodeposited from aqueous Zn(NO₃)₂ solution.The optimized deposition condition is 0.06mol/l～0.08mol/l,0.03A,70℃,10min～30min. The results according to the analysis of X-ray diffraction (XRD) and scanning electron micrograph(SEM) indicated that the ZnO films obtained had a compact hexagonal wurtzite type structure in preferable (002) growth direction.Under this circumstance,the ZnO thin film possess fine crystal status with grain size of 1μm,thickness of 1～2μm.3. The analysis of photoluminescence spectrum and cathode-luminescence spectrum on prepared ZnO thin filmThe photoluminescence spectra were measured by FLUOROLOG-3-TAU with a Xe-lamp and the cathode-luminescence spectra were performed by YFC—2 type CL testing device.The result showed that there is a sharp near UV emission peak located at 380nm³95nm and a strong orange-red emission peak located at 593nm⁶10nm are observed in the luminescence spectra of PL and CL,and there is little reports on the orange-red photoluminescence emission in ZnO films now.We also found that when the temperature for annealing increases(above 600℃), the photoluminescence with peak of 531nm and the green cathode-luminescence were observed.Therefore,annealing can not only improve the crystal quality,but also enhance green emission from ZnO film .4. The measurement of cathode-luminescence brightness in the ZnO film and the preparation of field emission display numeral-tube.We measured the luminescent brightness of cathode-luminescence in the field emission device with a luminescence meter and studied the affect of annealing on luminescent brightness. The results showed that the brightness of～2×10²cd/m² was obtained at electric field of 1.7V/μm.This result can meet the need of brightness the FED phosphor require.It also suggested that the annealing can improve the brightness of cathode-luminescence.Besides,in order to test the application value of deposited ZnO film,we prepared the field emission display diode by using it as anode phosphor and amorphous carbon films as cathode.