磁控共溅射法制备的Zn2GeO4多晶薄膜结构及其光致发光研究

用射频磁控共溅射方法在不同温度的单晶硅基片上生长薄膜，然后在800℃真空环境下对薄膜进行退火处理，成功获得了结晶状态良好的Zn₂GeO₄多晶薄膜.利用X射线衍射(XRD)，X射线光电子能谱(XPS)和原子力显微镜(AFM)对薄膜进行了结构、成分和形貌分析，研究了基片温度对三者的影响. 结果显示，当基片温度升高到400℃以上时，薄膜中的Zn₂GeO₄晶粒在(220)方向上显示出了明显的择优取向. 当基片温度在500—600℃范围内，有利于GeO₂结晶相的形成. XPS显示薄膜中存在着Zn₂GeO₄，GeO₂，GeO，ZnO四种化合态. 同时，随着基片温度的升高，晶粒尺寸增大且薄膜表面趋于平整. 薄膜的光致发光在绿光带存在中心波长为530和550nm两个峰，应该归因于主体材料Zn₂GeO₄中两个不同的Ge²⁺的发光中心. 关键词： 射频磁控溅射 2GeO₄')" href="#">Zn₂GeO₄ 荧光体

Structure and photoluminescence of Zn2GeO4 polycrystalline films prepared by radio-frequency magnetron sputtering

Films were deposited on Si substrates at different temperatures by RF magnetron sputtering and subsequently annealed in vacuum at 800℃. Well crystallized films were prepared successfully. The influences of substrate temperature on the structure, the componsition and the morphology of Zn₂GeO₄films were investigated by X-ray diffraction, X-ray photoelectron spectroscopy (XPS) and atom force microscope. The results show that Zn₂GeO₄ films grow with (220) preferred orientation with the increase of substrate temperature above 400℃, and the substrate temperature between 500 and 600℃ is suitable for GeO₂ crystalline growth. XPS spectra show that the films contain four chemical compositions of Zn₂GeO₄, GeO₂, Ge and ZnO. Besides, with the increase of substrates temperature, the size of crystal grains increases, and the surface of films is smooth and continuous. The green emission consisting of two peaks centered at 530 and 550nm, which is attributed to luminescence centers of Ge²⁺ substituting Zn²⁺ at different sites.