The Effect Of Al³⁺ Doping Quantity、Annealing Time On The Microstructural And Photoelectric Property Of ZAO Thin Films And Surface Modification

At present, the transparent conductive thin film as a kind of special materialform, it has become the materials research foundation of microelectronics,optoelectronics, magnetic electronics, material surface modification, sensor devices,solar cell, liquid crystal display and other emerging interdisciplinary. And in theforefront of the contemporary science and technology, the transparent conductive thinfilm has been widely used in various fields, especially for high and new technologyfields. Compared to the ITO thin film, Al doped ZnO (ZnO: Al, ZAO) film is notonly transparent and conductive, but also has the advantages of cheap, non-toxic, andit is more easily corroded and rich raw materials,. More importantly, it can stablyexist in the plasma of hydrogen stable environment. Judging from the current trend, ithas become one of the hot topics in the study of transparent conductive thin filmsinstead of the ITO films.Preparation methods of ZAO thin films are various, including vacuumevaporation, magnetron sputtering, pulsed laser deposition, molecular beam epitaxy,chemical vapor deposition and sol-gel method and so on. However, the sol-gelmethod is cheapy, no need of complex and expensive vacuum equipment,technological simply. The composion and the structure are controlled at the molecularlevel. As for the sol-gel method, the film uniformity is good, crystallizationtemperature is low and the film can be fabricated in a large area.In this paper, the sol-gel method is applied in the preparation of ZAO thin filmson the substrate of the glass. Selecting two hydrated zinc acetate as the reactionprecursor, monoethanolamine as a stabilizer, ethylene glycol methyl ether as a solvent,nine hydrated aluminum nitrate as a doping agent, the uniform clear solution of ZAOthin films is made. The rotation-coating method is used to coat on the substrate. TheZAO transparent and conductive thin films are finally prepared after drying, preheattreatment and post-heat treatment.Ultraviolet-visible-near infrared spectrophotometer, hall effect measurement,x-ray diffraction measurement, and scanning electron microscope have been used for studying the photoelectric properties and microstructures of ZAO thin films. Theresults show that the ZAO thin films are wurzite hexagonal structure with highpreferred orientation of c axis. The thin film surface is flat and level. Thetransmittance is more than85%in the visible range. The resistivity is reached10~2·cm. Meanwhile, the effect ofAl3+doping quantity、annealing time on themicrostructural and the photoelectric properties of ZAO thin films is analyzed. Theweak acid of ammonium chloride solution is used to modify the performances. Themicrostructural and the tansparent–conductive property are observed after thesurface modification.