Study Of Synthesis And Luminescence Properties Of ZnO@SnO₂ Transparent Conductive Thin Films With Coating Structure

The transparent conductive oxide films are widely used in the fields of solar cells, liquid crystal displays, plasma displays, antistatic coatings, semiconductor/insulator/semiconductor (SIS) hetero-junction, the windows of modern warplanes and cruise missiles. Many investigation reveal that the electricity property of ZnO transparent conductive thin film is deteriorated by the adsorption of oxygen on the surface and crystal grain boundary. The SnO2 transparent conductive thin film is difficut to be corroded. This limits the application of the above two transparent conductive thin films greatly. ZnO@SnO2 have the advantages of both ZnO and SnO2, which will be more propitious to hasten the studies and application of the transparent conducting thin films.In this thesis, the ZnO@SnO2 structure was prepared by the two steps gelation technique, which was based on the sol-gel method. The prepared samples were charicterized by the the X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS). The experimental results revealed that the ZnO@SnO2 was a chemical coating structure with cores of ZnO and shells of SnO2. The ZnO and SnO2 was bonded by the Zn-O-Sn net. The coating structure could in a better status when the Zn/Sn mol ratio was 8/12.Moreover, the optical and electrical properties of the ZnO@SnO2 samples were characterized by the NKD-8000e and four-probe measurements, respectively. The results show that the optical transmittance is higher than 80% in the visible range, and the lowest resistivity is 1.1×10-3Ω·cm When the doping content of Sb is 4at%, the annealing temperature is 600℃, and the mol ratio of Zn/Sn is 9/12. The effect of molar ratio of Zn/Sn, annealing temperature, doping concentration, film thickness etc on the transmittance and resistivity of ZnO@SnO2 sample was discussed.The photoluminescence of ZnO@SnO2 coating structure was investigated. It is found that the coating of SnO2 enhance the blue-ray emission of ZnO, because the coating structure of SnO2 increased the defect density of Zn vacanc, and increased the transition between the Zn to the Zn vacancy.