Measuring the spectral response of photoluminescence (SRPL) in solar cells has recently attracted attention as it can be used as a contactless relative measure of external quantum efficiency (EQE) prior to full device fabrication. However, this technique requires that the monitored PL spectrum originates mainly from a region in the solar cell with uniformly distributed majority carriers. For a stack of thin films with a similar material composition, the slightly different emission spectrum from each layer may lead to the superposition of several luminescence peaks. This letter presents the measurement of the SRPL from GaAsP tandem solar cells and outlines a method for separating the individual layer contributions. Good agreement between measured SRPL and EQE at short wavelengths has been achieved, and the deviations at longer wavelengths have been analyzed. This study also reveals unexpected bandgap narrowing resulting from a variable material composition within the active region.

中文翻译：

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在 SiGe/Si 系统上生长的 GaAs1-xPx 层的稳态光致发光的光谱响应

测量太阳能电池中光致发光 (SRPL) 的光谱响应最近引起了人们的注意，因为它可以在完整的器件制造之前用作外部量子效率 (EQE) 的非接触式相对测量。然而，该技术要求受监控的 PL 光谱主要来自太阳能电池中多数载流子均匀分布的区域。对于具有相似材料成分的堆叠薄膜，每层的发射光谱略有不同，可能会导致多个发光峰的叠加。这封信介绍了对 GaAsP 串联太阳能电池的 SRPL 的测量，并概述了分离各个层贡献的方法。在短波长测量的 SRPL 和 EQE 之间取得了良好的一致性，并分析了较长波长处的偏差。该研究还揭示了由有源区内的可变材料组成导致的意外带隙变窄。