The Preparation And Optical Properties Of ZnO Thin Films Co-doped With K-N By Ultrasonic Spray Pyrolysis Method

ZnO(Zinc oxide)is a II—VI n-type semiconductor material with wide direct band gap of 3.37eV.On the condition of room temperature,it has a large exciton binding energy of 60meV,because of its excellent properties of optical and electrical,ZnO has important applications prospect in LED,gas sensor,solar cells,pressure sensitive resistance,and other fields.Researches show that ZnO materials which have been doped have more excellent performance.This thesis summarized crystal structure and optical properties of the doped ZnO film in details,discussed the advantages and disadvantages of various preparation method of thin film.For the advantage of low cost,easy operation,this thesis used the ultrasonic spray pyrolysis method(USP)to prepare ZnO thin films and studied the effect of different doped impurity to ZnO thin film properties.On the basis of the optimization of experimental parameters,zinc acetate,ammonium chloride was used as the precursor solution to prepare N doped films.Zn(CH3COO)2 · 2H2O,NH4Cl and KCl were used as the precursor solution to prepare K-N co-doped thin films.X-ray diffraction(XRD),scanning electron microscope(SEM),photoluminescence(PL),Ultraviolet visble transmission spectrum(UV-VIS)were used to characterize the structure,morphology and optical properties.The experimental results showed that when the substrate temperature was 480 ? and carrier gas flow rate was 1.0 L/min,the property of N doped film was optimal,and they appeared the growth of the C axis preferred orientation,but when the substrate temperature raised further,the growth preferred orientation would occur an offset.In K-N co-doped thin films,by changing the concentration of K+ doping,the quality of the crystallization of ZnO thin films and the optical properties would approve to some extent.When the precursor solution concentration was 0.025mol/L,the substrate temperature was 480 ?,the carrier gas flow rate was 1.0L/min,the K-N co-doped ZnO thin films had the best excellent crystallization and optical properties.