Study On Preparation And Structural, Electrical And Optical Properties Of Polycrystalline Zinc Oxide Films

Polycrystalline zinc oxide(ZnO) films are one of very useful materials and arewidely used in piezoelectric device, transparent conducting electrodes,optoelectric device and gas sensors because of their excellent characteristics. Inthis dissertation, we report the systematical work on preparation, and thestructural, electrical, and optical properties of polycrystalline ZnO films.ZnO films were deposited on silicon(Si) and glass substrate by reactive radiofrequency sputtering(RF) technique with zinc target in the mixed gas of Ar andO2. Zinc target has obvious advantage over ZnO targets used by otherresearchers because of little contamination and low cost. A creative co-sputtering method of lying some aluminum(Al) chips on target was employed todeposit Al-doped ZnO films(AZO). In this way, the Al content in films can becontrolled easily compared with that of ZnO target.The effect of deposition condition, included RF power, substrate temperature,the ratio of O2 to Ar in mixed gas and the position of substrate on the structuralproperties of ZnO films has be studied in considerable detail. It is found that theoptimal conditions to deposit ZnO are below: substrate temperature of 400, RFpower of 120W, and the ratio of O2 to Ar of 40%. The average opticaltransmittance in the wavelength range from 3000? to 11000?, the full width athalf maximum(FWHM)and the packing density of ZnO films are 86%, 0.2deg.and 97%, respectively. The surface morphology shows a closed-packedcolumnar grain indicated by atomic force microscope(AFM). X-rayphotoelectron spectrometer(XPS) analysis indicated the existence of Al. Thefilms have a highly oriented growth characteristics with the c-axis perpendicular...