The germanium auto‐diffusion effects on the inter‐atomic distance between the nearest neighbors of the Ga atom in GaP epilayers are investigated using high‐resolution X‐ray diffraction (HRXRD) and X‐ray absorption spectroscopy. The GaP layers grown on Ge (111) are structurally coherent and relaxed but they show the presence of residual strain which is attributed to the auto‐diffusion of Ge from the results of secondary ion mass spectrometry and electrochemical capacitance voltage measurements. Subsequently, the inter‐atomic distances between the nearest neighbors of Ga atom in GaP are determined from X‐ray absorption fine‐structure spectra performed at the Ga K‐edge. The estimated local bond lengths of Ga with its first and second nearest neighbors show asymmetric variation for the in‐plane and out‐of‐plane direction of GaP/Ge(111). The magnitude and direction of in‐plane and out‐of‐plane microscopic residual strain present in the GaP/Ge are calculated from the difference in bond lengths which explains the presence of macroscopic residual tensile strain estimated from HRXRD. Modified nearest neighbor configurations of Ga in the auto‐diffused GaP epilayer are proposed for new possibilities within the GaP/Ge hetero‐structure, such as the conversion from indirect to direct band structures and engineering the tensile strain quantum dot structures on (111) surfaces.

中文翻译：

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X射线吸收光谱研究锗自动扩散对GaP / Ge（111）中Ga和P原子键长的影响

使用高分辨率X射线衍射（HRXRD）和X射线吸收光谱法研究了锗对GaP外延层中Ga原子的最邻近邻居之间原子间距离的自动扩散效应。在Ge（111）上生长的GaP层在结构上是连贯且松弛的，但它们显示出残余应变的存在，这归因于二次离子质谱和电化学电容电压测量的结果，Ge的自动扩散。随后，根据在Ga K上进行的X射线吸收精细结构光谱确定GaP中Ga原子的最邻近原子之间的原子间距离-边缘。Ga的第一和第二最近邻的估计局部键长在GaP / Ge（111）的面内和面外方向上显示出不对称变化。GaP / Ge中存在的平面内和平面外微观残余应变的大小和方向是根据键长的差异计算得出的，这解释了根据HRXRD估算的宏观残余拉伸应变的存在。提出了GaP / Ge异质结构中Ga的新的可能可能性，例如Gain / Ge异质结构中Ga的最近邻构型的修饰，例如从间接带结构转换为直接带结构以及在（111）表面上设计拉伸应变量子点结构。