Structural, Morphological and Optical Properties of ZnO Thin Films Grown on γ-LiA1O₂ Substrate by Pulsed Laser Deposition

Jun ZOU, Shengming ZHOU, Xia ZHANG, Fenglian SU, Xiaomin LI and Jun XU Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China Graduate School, Chinese Academy of Sciences, Beijing 100039, China Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, China Anhui University, Hefei 230039, China

摘 要：<正>ZnO thin films were deposited on the substrates of （100） γ-LiAIO2 at 400, 550 and 700℃using pulsed laser deposition （PLD） with the fixed oxygen pressure of 20 Pa, respectively. When the substrate temperature is 400℃, the grain size of the film is less than 1μm observed by Leitz microscope and measured by X-ray diffraction （XRD）. As the substrate temperature increases to 550℃, highly-preferred c-orientation and high-quality ZnO film can be attained. While the substrate temperature rises to 700℃, more defects appears on the surface of film and the ZnO films become polycrystalline again possibly because more Li of the substrate diffused into the ZnO film at high substrate temperature. The photoluminescence （PL） spectra of ZnO films at room temperature show the blue emission peaks centered at 430 nm. We suggest that the blue emission corresponds to the electron transition from the level of interstitial Zn to the valence band. Meanwhile, the films grown on 7-LiAIO2 （LAO） exhibit green emission centered at 540 nm, which seemed to be ascribed to excess zinc and/or oxygen vacancy in the ZnO films caused by diffusion of Li from the substrates into the films during the deposition.

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