The Preparation And Characteristics Of Zinc Oxide Thin Films By Rare-Earth Dy,La And CeO₂ Doped

The ZnO thin films and ZnO by Dy,La and CeO₂ doping thin films were prepared by vacuum thermal evaporation with two steps on glass substrates.The influences of the process conditions,doping,heat treatment temperature and time on crystalline structure,crystalline grain dimension,surface topography,electrical, optical and sensitive parameters characteristics of ZnO films were analyed in detail. The characteristics of films were tested by XRD,SEM,ultraviolet-visible spectrophotometer.The experimental results showed that the Zn powder as evaporation matter to prepare thin films and ZnO thin films by Dy,La and CeO₂ doping then heat treatment(T=500-550℃,O₂ by 500ml/min) can obtain the ZnO wurtzite thin films.When the heat treatment condition with T=500℃,t=45min,the good performance(002) plane and the average dimension of the crystal grains was about 27.979nm.When doping component was even with Dy,La and CeO₂,we can obtain the ZnO thin films with performance(002) plane was restrained and the resistance of thin film was reduced.The SEM results showed that the surface of ZnO thin films with acerata structure,but the grain is anomalous hexagon.The gather phenomenon of particles was obvious and the particles were not uniform on surface of the ZnO thin films without Dy,La and CeO₂ doping.But the gather phenomenon of particles was not obvious and the particles were uniform on surface of the ZnO thin films by Dy,La and CeO₂ doping.It was shown from the experiment that the transmissivity of ZnO thin films (350-900nm)was 80%,the Dy,La and CeO₂-doping will reduce the transmissivity of ZnO thin films.The optical band gap of ZnO thin films was 3.34eV,the Dy,La and CeO₂-doping will reduce the optical band gap of ZnO thin films within 3.20-3.31eV.The results of gas sensitivity characteristic test were by static method.The working-temperature of ZnO thin films was droped by Dy,La and CeO₂ -doping.And the gas sensitivity characteristics to ethanol and acetone were improvemented.The texting-temperature with 250℃,the consistence of ethanol and acetone with 6×10^-3,ZnO thin films by Dy,La and CeO₂ -doping have good gas sensitivity to ethanol and acetone.ZnO thin films by Dy 3at%,La-doping have good gas sensitivity to ethanol with 25,35.ZnO thin films by CeO₂ 9at%-doping have good gas sensitivity to ethanol with 35.ZnO thin films by Dy 3at%,La-doping have good gas sensitivity to acetone with 50,38.ZnO thin films by CeO₂ 9at%-doping have good gas sensitivity to acetone with 45.