Preparation And Properties Of Zinc/Tin Oxide Composite Transparent Conductive Films

Transparent conductive oxide films(TCO), with good electrical conductivity and hightransmittance in the visible-near infrared, have been widely used in thin-film solar cells, largearea flat panel display, oganic light emitting diodes, low emissivity glass, transparent thin filmtransistor, flexible electronic devices and other areas. At present, most of commercial TCOmaterials are ITO films，but there are still many shortcomings. Zinc oxide is a wide band gapsemiconductor material, with low price, non-toxic, non-polluting, environmentally compatible,suitable for the production of large area, easy doping and the stability better than ITO films,etc. Therefore, ZnO-based transparent conductive film is most likely to replace the ITO film.However, we found that there are a lot of basic research or technical bottlenecks ofZnO-based materials need to be improved and breakthroughs. In order to solve theseproblems, we carried out the research and obtained following results:We prepared graphene/ZnO composite transparent conductive film by in-situ synthesis.The results show that the graphene/zinc oxide composite transparent conductive films are ingood growth under the vacuum annealing environment; Raman spectroscopy confirm that thezinc oxide and graphene can be simultaneously obtained by thermal decomposition.We prepared a series of tin-doped zinc oxide films by sol-gel process. The results showthat the annealing temperature have great effect on the properties. XRD of (002) diffractionpeak intensity first increased and then decreased, the film have best structure at450℃;annealing temperature has little effect on the optical transmittance, but the increasingannealing temperature makes the band gap showed a downward trend; and the increasing ofthe Sn doping concentration makes the absorption edge shifted to shorter wavelength and theoptical band gap larger. When the Sn doping concentration is2at.%, the transmittance of ZTOfilm is nearly90%, the crystal grain surface fluctuation is steady.We deposited Al-doped of ZnO TCO films by DC magnetron sputtering. The resultsshowed that the film sample preparation exhibited c-axis preferred orientation, thetransmittance in the visible wavelength region is not affected by the sputtering power, whenthe sputtering power is120W, the film growth best, the grain size reached a maximum, Thelowest resistance of sample was207Ω/口. We prepared a series of graphene-doped tin oxide films by sol-gel process. The resultsshowed that the crystalline quality of SnO2thin films is improved with the doping of graphene,and the optical band edge of film sample moves towards long-wave direction, causing “redshift” phenomenon. Moreover, the photoluminescence intensity of the SnO2thin filmsgradually decreased with the increase of the content of graphene due to the concentrationquenching effect.The results of this paper provide experimental evidence for improving the structure andphotoelectric performance of ZnO thin films. Meanwhile, it provide important reference valueof theoretical basis and experimental methods for the prepartion of ZnO-based transparentconductive films and development of ZnO thin-film photovoltaic devices.