Rutile-type GeO2 (r-GeO2) with an ultrawide bandgap of ∼4.7 eV has emerged as a promising material for next-generation power-electronic and optoelectronic devices. We performed transmission electron microscopy (TEM) observation to analyze the structural properties of r-GeO2 film on r-TiO2 (001) substrate at an atomic level. The r-GeO2 film exhibits a threading dislocation density of 3.6 × 109 cm−2 and there exist edge-, screw-, and mixed-type dislocations in the film as demonstrated by two-beam TEM. The edge-type dislocations have Burgers vectors of [100] and/or [110]. The bandgap of the r-GeO2 film is 4.74 ± 0.01 eV as determined by electron energy loss spectroscopy.

中文翻译：

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TiO2 （001） 衬底上金红石型 GeO2 薄膜的透射电镜研究


具有 ∼4.7 eV 超宽带隙的金红石型 GeO2 （r-GeO2） 已成为下一代电力电子和光电器件的有前途的材料。我们进行了透射电子显微镜 （TEM） 观察，以在原子水平上分析 r-TiO2 （001） 衬底上 r-GeO2 薄膜的结构特性。r-GeO2 薄膜的螺纹位错密度为 3.6 × 109 cm-2，并且薄膜中存在边缘、螺钉和混合型位错，如双光束 TEM 所示。边型位错的 Burgers 向量为 [100] 和/或 [110]。r-GeO2 薄膜的带隙为 4.74 ± 0.01 eV，由电子能量损失光谱确定。