Research On Properties Of Aluminum-doped ZnO Thin Films Prepared By Sol-Gel Technique

ZnO film is a novel Ⅱ-Ⅵ direct compound semiconductor with wide band gap energy of 3.37eV and a exciton binding energy 60meV at room temperature.Due to its the prerequisite for visible or ultraviolet light emission at room temperature,it has the tremendous potential applications for ultraviolet detectors,LEDs,LDs.ZnO thin film is used widely and effectively in the fields of surface acoustic wave devices,solar cell,gas sensors,varistors and so on because of its excellent piezoelectrical performance.In this paper, the Al3+-doped ZnO thin films were prepared on Na-Ca-Si glass substrate (microscope slides) by Sol-Gel process from 2-methoxyethanol solution prepared by Zinc acetate as premonitor,monoethanolamine as stabilizator and aluminum chloride reaction.Homogenous,transparent,polycrystalline ZnO thin film was formed finally by diping coating conducted for film-plate on substrate, drying, pre-heat-treatment, anealing.Prepared technical parameters were optimized by L9(34) experiment analysis.A unique method for cleaning and drying of substrate-cleaning used by scour,drying used by infrared light was fished out by large numbers of experiment.Chemical mechnism of ZnO thin film prepared by Sol-Gel technique was discussed by DTA for the first time.By the measurements of SEM,XRD and UVS,the thin film was analysed.The result proved that the thin film with strongly preferred orientation of C-axis perpendicular to the substrate surface which surface was homogenous,dense and crackfree was the crystalline phase of hexagonal wurtzite.The thin film was composed of plentiful asteroidal crystal which crystal dimension approximately 10～30nm.The average transmittance of thin film in visible region was above 90%.The results of measurements else also proved that the thickness of single dip-coating was 75～240nm,this films resistivity was found to be 3.105×102～3.96×105Ω·cm.The thickness and resistivity of thin film influenced by dope-content, withdrawal speed,pre-heat-treatment,anealing were reseached respectively.