The Preparation Of ZnO(Cu:ZnO) Films And The Exploration On Electroluminescence Of The Films

Zinc oxide is a multi-function and wide-band-gap semiconductor material, withthe direct band gap of3.37eV and the exciton’s bounding energy of60meV at roomtemperature. Zinc oxide not only has the good conductive properties and excellentphotoelectric characteristics, but also can emit much color light due to varied pointdefects, which has drawn more and more attentions of many scholars.Electroluminescent device that can directly convert electical energy to optical energyhas been widely applied into flat-panel display and civil illumination, for its fastresponse, low energy consumption, light weight, low cost, simple device structure,environmental protection and so on.In this paper, material properties, application principles and research progressesof ZnO films, Cu:ZnO films and film electroluminescent devices were introduced,and all the experimental process was presented in detail. And sol-gel method was usedto prepare ZnO thin films. High quality of ZnO thin films are obtained by carefullychosing experimental conditions and the deep researching on its structure, surfacemorphology, photoluminescence, transmission and absorption spectrums. ZnO thinfilm electroluminescent devices were fabricated by using traditionalmetal-semiconductor and metal-insulator-semiconductor device structures and theelectrically stimulating luminous phenomenon was explored. The I-V characteristicsand electroluminescence of ZnO thin films were checked on by KEITHLEY2400andPR650spectral photometer respectively. Test results are analyzed and discussedfinally. In addition, we also used sol-gel methods to prepare the Cu doped ZnO thinfilms. And the affection of experimental conditions on the quality of films and theblue light emission intensity was explored. The main conclusions of this paper are asfollows:(1) ZnO thin films prepared by0.6mol/L concentration of sol, preheatingtemperature of200℃, film thickness for258nm, annealing processing temperature of500℃are dense uniform of surface, high quality, have a compact hexagonal wurtzitetype structure and excellent optical performance.(2) We observed the visible light emitting in dark room at room temperature, byadding dc voltage on ZnO thin film devices of MS and MIS structure. (3) Insulating layer not only can prevent device from puncture, but also improvethe brightness and efficiency of device because of providing vacancies.(4) Cu doping with appropriate concentration could get high quality ZnO filmsand could get high strength blue light emission under low temperature annealing.