We have investigated the solid-phase epitaxial crystallization of β-Ga₂O₃ thin films on NiO (111) (3 nm thick)-buffered α-Al₂O₃ (0001) substrates prepared by pulsed KrF excimer laser irradiation onto amorphous Ga₂O₃ thin films from the backside of the substrate at room temperature. The results of x-ray diffraction, reflection high-energy electron diffraction, and transmission electron microscopy indicated that the solid-phase crystallization of the amorphous Ga₂O₃ thin film to epitaxial β-Ga₂O₃ film started from the film/substrate interface toward the film surface with an average growth rate of about 0.1 nm thickness per one pulse irradiation. The optical bandgap of the epitaxial β-Ga₂O₃ thin films (∼80 nm thick) was estimated to be 4.9 eV from the UV/Vis transmittance measurement.

中文翻译：

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在室温下，从 NiO (111) 缓冲的 α-Al2O3(0001) 衬底背面通过 KrF 准分子激光照射固相外延结晶 β-Ga2O3 薄膜

我们研究了 β-Ga ₂ O ₃薄膜在 NiO (111)（3 nm 厚）缓冲的 α-Al ₂ O ₃ (0001) 衬底上的固相外延结晶，该衬底通过脉冲 KrF 准分子激光照射非晶 Ga室温下基板背面的₂ O ₃薄膜。X射线衍射、反射高能电子衍射和透射电镜结果表明，非晶Ga ₂ O ₃薄膜固相结晶为外延β-Ga ₂ O ₃薄膜从薄膜/基材界面向薄膜表面开始，每次脉冲照射的平均生长速率约为 0.1 nm。根据紫外/可见光透射率测量，外延 β-Ga ₂ O ₃薄膜（约 80 nm 厚）的光学带隙估计为 4.9 eV。