Abstract The effects of irradiation with 3 MeV alpha particles on the microstructure and photoluminescence (PL) emission of ZnO thin films were investigated as a function of exposure time between 100 s and 8 h. The analysis of atomic force microscopy (AFM) data reveals modifications of the surface morphology when the irradiation periods exceed 500 s. The roughness of the films exposed for 500 s and 1000 s slightly decreases. The surface becomes almost flat after 8 h irradiation, showing a small density of randomly distributed large aggregates, increased crystallite size and reduced lattice strain and residual stress. The PL spectra of pristine ZnO films present the main characteristic emission bands at 3.25 eV and 2.75 eV. The emission band at 2.75 eV is quenched after irradiation for 100 s, but recovers constantly for irradiation times increasing to 500 s and 1000 s. New emission bands appear at 2.80 eV in the PL spectra of the films exposed to radiation for 500 s, and at 3.10 eV, 3.00 eV, 2.66 eV and 2.64 eV, when the irradiation time increases to 1000 s. The time evolution of radiation induced defects is discussed in relationship with the PL data, the morphology of the films and details of first principles electronic structure of defective models.

中文翻译：

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用 3 MeV α 粒子照射 ZnO 薄膜的微观结构和光致发光的演变

摘要 研究了 3 MeV α 粒子辐照对 ZnO 薄膜的微观结构和光致发光 (PL) 发射的影响，作为 100 秒和 8 小时之间曝光时间的函数。原子力显微镜 (AFM) 数据的分析揭示了当辐照时间超过 500 秒时表面形态的变化。暴露 500 秒和 1000 秒的薄膜粗糙度略有下降。照射 8 小时后，表面变得几乎平坦，显示出小密度随机分布的大聚集体，晶粒尺寸增加，晶格应变和残余应力降低。原始 ZnO 薄膜的 PL 光谱在 3.25 eV 和 2.75 eV 处呈现主要特征发射带。2.75 eV 的发射带在照射 100 秒后淬灭，但在辐照时间增加到 500 秒和 1000 秒时不断恢复。当辐照时间增加到 1000 秒时，暴露于辐射 500 s 的薄膜的 PL 光谱中出现新的发射带，在 3.10 eV、3.00 eV、2.66 eV 和 2.64 eV。辐射诱导缺陷的时间演变与 PL 数据、薄膜的形态和缺陷模型的第一原理电子结构的细节的关系进行了讨论。