Boron-doped Czochralski (Cz) Si is the most commonly used semiconductor in the fabrication of solar cells. The minority carrier lifetime of boron-doped Cz Si decreases upon exposure to light due to B–O-related defects, which reduce the performance of ∼10⁹ solar modules worldwide. Using electron paramagnetic resonance (EPR), we have identified the spin-active paramagnetic signatures of this phenomenon and gained insights into its microscopic mechanism. We found a distinct defect signature, which diminished when the degraded sample was annealed. The second signature, a broad magnetic field spectrum, due to the unionized B acceptors, was present in the annealed state but vanished upon light exposure. These observations show that, on degradation, nearly all the ∼10¹⁶ cm⁻³ B atoms in Cz Si complexed with interstitial O atoms, whereas only ∼10¹² cm⁻³ of these complexes created defects that were recombination-active. The formation rate of these recombination-active defects correlated with the decay of the minority carrier lifetime. The line shape parameters linked these defects to both B and O impurities in Cz Si.

中文翻译：

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掺硼直拉硅太阳能电池中光致效率降低缺陷的原子结构

掺硼直拉 (Cz) Si 是太阳能电池制造中最常用的半导体。由于与 B-O 相关的缺陷，硼掺杂的 Cz Si 的少数载流子寿命在暴露于光时会降低，这会降低全球约^{10 9}太阳能模块的性能。使用电子顺磁共振 (EPR)，我们已经确定了这种现象的自旋活性顺磁特征，并深入了解了其微观机制。我们发现了一个明显的缺陷特征，当退化的样品退火时，缺陷特征会减少。第二个特征，宽的磁场光谱，由于未结合的 B 受体，在退火状态下存在，但在曝光后消失。这些观察表明，在降解时，几乎所有的 ∼10 ¹⁶ cm ^-3Cz Si 中的 B 原子与间隙 O 原子复合，而这些复合物中只有约^{10 12} cm ^-3产生具有复合活性的缺陷。这些复合活性缺陷的形成速率与少数载流子寿命的衰减相关。线形参数将这些缺陷与 Cz Si 中的 B 和 O 杂质联系起来。