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在高真空条件下,采用脉冲激光沉积法在Si(111)衬底上制备了高度(111)取向的CeO2薄膜。使用反射高能电子衍射仪对薄膜制备过程进行了原位监测,衍射花样为清晰条纹状,显示薄膜结晶质量较好,表面平整光滑。采用X射线衍射仪对不同衬底温度、不同激光能量制备的薄膜进行了结构表征,随着温度升高和能量增强,CeO2薄膜(111)峰逐渐增强且峰位越来越靠近标准峰位,表明CeO2薄膜的取向性变好且薄膜应力逐渐下降。通过椭偏仪对薄膜的折射率进行了表征,结果表明薄膜的光学性能强烈依赖其结晶质量,结晶质量最好的样品折射率接近单晶薄膜。使用高分辨透射电镜表征了样品的横断面,照片显示薄膜内部原子排列有序,结晶质量较好,部分区域与衬底取向略有偏差。
High-orientation (111) CeO2 thin films were deposited on Si (111) substrates by pulsed laser deposition under high vacuum conditions. In-situ monitoring of the film preparation process using a reflection high-energy electron diffractometer showed that the diffraction pattern was clear stripe, indicating that the film has better crystal quality and a smooth surface. The films prepared by different substrate temperatures and different laser energies were characterized by X-ray diffraction (XRD). With the increase of temperature and energy, the (111) peak of CeO2 film gradually increased and the peak position was closer to the standard peak position. It shows that the orientation of CeO2 thin films is better and the stress of thin films is gradually decreased. The refractive index of the film was characterized by ellipsometry. The results show that the optical properties of the film are strongly dependent on the crystal quality. The refractive index of the sample with the best crystal quality is close to that of the single crystal film. High-resolution transmission electron microscopy was used to characterize the cross-section of the sample. The photographs show that the atoms in the film are arranged in order, the crystal quality is good, and some regions are slightly deviated from the substrate orientation.