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Abstract：
Multilayer III-V-based solar cells are complex devices consisting of many layers and interfaces. The study and the comprehension of the mechanisms that take place at the interfaces is crucial for efficiency improvement. In this work, we apply frequency-modulated Kelvin probe force microscopy under ambient conditions to investigate the capability of this technique for the analysis of an InP/GaInAs(P) multilayer stack. KPFM reveals a strong dependence on the local doping concentration, allowing for the detection of the surface potential of layers with a resolution as low as 20 nm. The analysis of the surface potential allowed for the identification of space charge regions and, thus, the presence of several junctions along the stack. Furthermore, a contrast enhancement in the surface potential image was observed when KPFM was performed under illumination, which is analysed in terms of the reduction of surface band bending induced by surface defects by photogenerated carrier distributions. The analysis of the KPFM data was assisted by means of theoretical modelling simulating the energy bands profile and KPFM measurements.
摘要：
多层III-V型太阳能电池是由许多层和界面组成的复杂器件。对接口处发生的机制的研究和理解对于提高效率至关重要。在这项工作中,我们在环境条件下应用调频开尔文探针力显微镜来研究该技术用于分析InP/GaInAs（P）多层堆叠的能力。KPFM揭示了对局部掺杂浓度的强烈依赖性，允许以低至20nm的分辨率检测层的表面电位。对表面电势的分析允许识别空间电荷区域和，因此，沿堆栈的几个结的存在。此外，当在照明下进行KPFM时，观察到表面电势图像的对比度增强，根据光生载流子分布对表面缺陷引起的表面带弯曲的减少进行了分析。通过模拟能带轮廓和KPFM测量的理论建模来辅助KPFM数据的分析。
