Quantum confinement effect in high quality nanostructured CeO2 thin films
Quantum confinement effect in high quality nanostructured CeO2 thin films
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DOI：
10.1063/1.2841719
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发表时间：
2008-03
影响因子：
3.2
通讯作者：
J. Nie;Z. Hua;R. Dou;Q. Tu
中科院分区：
文献类型：
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作者：
J. Nie;Z. Hua;R. Dou;Q. Tu
通过脉冲激光沉积在 R 切割蓝宝石基板上制备了高质量晶体纳米结构 CeO2 薄膜。通过原子力显微镜、X 射线衍射以及光学透射和反射光谱研究了生长态和退火后（在氧气中）的薄膜。随着微观结构从小晶粒到大的准二维岛的变化，光谱也发生变化。因此，发现带隙能量（Eg）随着晶粒尺寸的减小而系统地增加，直接跃迁的带隙能量（Eg）范围为3.58至3.71eV，间接跃迁的范围为3.01至3.26eV。这与量子限制模型一致，但迄今为止，尚未在 CeO2 薄膜中以令人信服的方式观察到。结果表明，可以通过厚度控制和后退火来控制纳米结构薄膜中的 Eg。
High quality crystalline nanostructured CeO2 thin films were fabricated by pulsed laser deposition on R-cut sapphire substrates. As-grown and postannealed (in oxygen) films were investigated by atomic force microscopy, x-ray diffraction, and optical transmission and reflectance spectroscopy. The optical spectra changed as the microstructure varied from small grains to large quasi-two-dimensional islands. Hence, the band gap energy (Eg) was found to increase systematically with the decrease in the grain size and ranged from 3.58to3.71eV for the direct and from 3.01to3.26eV for the indirect transitions. This is consistent with the quantum confinement model and, up to now, not observed in a convincing manner in the CeO2 thin films. Results indicate that Eg can be controlled in nanostructured thin films through thickness control and postannealing.