Mg_xZn_(1-x)O薄膜的红外光谱及其表面浸润性

Surface Wettability and Infrared Spectrum of Mg-Doped ZnO Coatings

采用溶胶-凝胶法制备MgxZn1-xO薄膜,利用X射线衍射仪、原子力显微镜、傅里叶变换红外光谱仪和荧光光谱仪等测试分析薄膜的微结构、表面形貌、红外光谱和光致发光特性等,研究结果表明,薄膜中的Zn O成分均呈六角纤锌矿结构,当x=0.15时,薄膜中有Mg O成分析出;随着x从0增大到0.15,均方根粗糙度不断减小;1038 cm-1附近的吸收峰对应于Si-O-Si的对称和反对称伸缩振动模,408 cm-1附近的吸收峰对应于六角结构Zn O的Zn-O振动模,900 cm-1附近的吸收峰则对应于SiO键伸缩振动模,该吸收峰强度的减弱说明薄膜中Si-O键数目减少。近带边发射峰位由410 nm蓝移到370 nm与薄膜导带底或价带顶的局域能级、薄膜禁带宽度变化等因素有关,可见光发射带是单离子氧空位(VO+)和氧填隙(Oi)等薄膜本征缺陷相互竞争的结果。用接触角测试仪测试薄膜的表面接触角,研究Mg含量对薄膜的表面浸润性及其光诱导可逆转变的影响,并探讨其形成机理。

The Mg-doped ZnO （MgxZn1_ xO）coatings were synthesized on Si substrate in sol-gel method. The im- pacts of the Mg-content on the microstructures, optical properties, and wettability of the ZnO coatings were investigated. The Mg-doped ZnO films were characterized with X-ray diffraction, atomic force microscopy, Fourier transformation infrared spectroscopy,and fluorescence spectrophotometer. The results show that the Mg-content strongly affects the photo- mission characteristics and wettability of the hexagonal wurtzite-phased ZnO coatings. As the Mg-content（ x ）increased to 0.15,the RMS surface roughness gradually decreased, and when x = 0.15 , surface segregation of MgO was observed; the emission peak near the band edge was found to blue shift from 410 to 370 nm. In addition, UV-irradiation converted wet-tability of the MgxZn1-xO coatings from hydrophobicity to hydrophilicity. Possible mechanisms responsible for the dependence of wettability on Mg-content and photo-induced conversion of wettability were also tentatively discussed.