Abstract Aberration-corrected scanning transmission electron microscopy (STEM) and electron energy loss spectroscopy (EELS) investigations have been applied to investigate the structure and composition fluctuations near interfaces in wafer-bonded multi-junction solar cells. Multi-junction solar cells are of particular interest since efficiencies well above 40% have been obtained for concentrator solar cells which are based on III-V compound semiconductors. In this methodologically oriented investigation, we explore the potential of combining aberration-corrected high-angle annular dark-field STEM imaging (HAADF-STEM) with spectroscopic techniques, such as EELS and energy-dispersive X-ray spectroscopy (EDXS), and with high-resolution transmission electron microscopy (HR-TEM), in order to analyze the effects of fast atom beam (FAB) and ion beam bombardment (IB) activation treatments on the structure and composition of bonding interfaces of wafer-bonded solar cells on Si substrates. Investigations using STEM/EELS are able to measure quantitatively and with high precision the widths and the fluctuations in element distributions within amorphous interface layers of nanometer extensions, including those of light elements. Such measurements allow the control of the activation treatments and thus support assessing electrical conductivity phenomena connected with impurity and dopant distributions near interfaces for optimized performance of the solar cells.

中文翻译：

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晶圆键合多结太阳能电池中 GaAs/Si 界面的像差校正透射电子显微镜分析

摘要 像差校正扫描透射电子显微镜 (STEM) 和电子能量损失光谱 (EELS) 研究已被应用于研究晶片键合多结太阳能电池界面附近的结构和成分波动。多结太阳能电池受到特别关注，因为基于 III-V 族化合物半导体的聚光太阳能电池的效率已远高于 40%。在这项以方法论为导向的研究中，我们探索了将像差校正的高角度环形暗场 STEM 成像 (HAADF-STEM) 与光谱技术（如 EELS 和能量色散 X 射线光谱（EDXS））相结合的潜力，以及高分辨率透射电子显微镜（HR-TEM），为了分析快速原子束（FAB）和离子束轰击（IB）活化处理对硅衬底上硅片键合太阳能电池键合界面结构和组成的影响。使用 STEM/EELS 的研究能够以高精度定量测量纳米延伸的非晶界面层内元素分布的宽度和波动，包括​​轻元素的元素分布。这种测量允许控制活化处理，从而支持评估与界面附近的杂质和掺杂剂分布相关的电导率现象，以优化太阳能电池的性能。使用 STEM/EELS 的研究能够以高精度定量测量纳米延伸的非晶界面层内元素分布的宽度和波动，包括​​轻元素的元素分布。这种测量允许控制活化处理，从而支持评估与界面附近的杂质和掺杂剂分布相关的电导率现象，以优化太阳能电池的性能。使用 STEM/EELS 的研究能够以高精度定量测量纳米延伸的非晶界面层内元素分布的宽度和波动，包括​​轻元素的元素分布。这种测量允许控制活化处理，从而支持评估与界面附近的杂质和掺杂剂分布相关的电导率现象，以优化太阳能电池的性能。