The Preparation And Properties Of ZnO: Al Thin Film

ZnO is a novel semiconductor material with wide direct band gap （3.37eV）. Due toits unique electrical and optical properties, ZnO is widely used in all kinds ofoptoeletronic devices. Aluminum-doped zinc oxide （AZO） thin films with lowresistivity and high transparency in visible range are promising as alternatives to ITO（In₂O₃:Sn） for transparent conducting oxide.In this paper, transparent, polycrystalline AZO thin film are prepared by RFmagnetron sputtering using a zinc oxide target doped with Al2O3（2wt%） on commonfloating glass. And the effect of sputtering power and buffer layer on the structural,optoelectronic properties of the AZO films is investigated. Researches and results are asfollows.AZO thin films are deposited on glass by magnetron sputtering method, and thesputtering power are60W,100W,140W and180W respectively. Annealing treatmentfor as-deposited samples are characterized by some test equipment. The results showthat: each of the films has a preferential c-axis orientation, the crystalline quality ofAZO films are affected by sputtering power, performed the best quality under140W ofsputtering power. All the films exhibit a high transmittance in visible region, andslightly decrease with increasing power. As sputtering power changes, the resistivity isaffected by the energy of deposited particles and the structure of crystal, The lowestresistivity of1.5×103Ω cmcan be obtained when the sputtering power is140W.AZO films with Al2O3and AZO buffer layers are deposited. The influence on thefeature of AZO film with different buffer layers is analyzed. After testing the propertiesof samples, the results show that: the buffer layer plays a very good transition, becauseit can effectively alleviate the lattice mismatch and thermal mismatch between films andsubstrate materials. The films prepare on Al2O3and AZO buffer layers with better c-axispreferred orientation, smooth surface, and the crystal quality has been enhanced; Thetransmittance in ultraviolet-visible region is higher than80%; The conductivity of thefilm is also improved, and exhibits a lowest resistivity of6.7×104Ω cm. At the sametime, this experiment also proves that the mitigation capacity of buffer layer is strongerwhen using the intrinsic buffer layer.