Liquid phase crystallized silicon solar cells on glass have recently demonstrated 15.1% efficiency using a heterojunction interdigitated back contact cell architecture and an absorber thickness of 14 $\mu$m. One of the key enabling developments was a new method to first passivate electron contact fingers with a-Si:H(i) and then locally laser fire them to maintain a low contact resistance. In this work, high resolution, light-beam induced current measurements (LBIC) were used to analyze this approach. Charge collection was observed to have increased from 0.13 ${\text{mAcm}}^{-2}$ to 0.9 ${\text{mAcm}}^{-2}$ under the electron contact which is a sevenfold increase. Using 520, 642, 932, and 1067 nm wavelengths of incident light, external quantum efficiency was mapped in regions including grain boundaries, dislocation defects, shunts, defect-free regions, and laser fired spots. Reduction of charge collection in the laser fired spots was limited to diameters of 50–20 $\mu$m, depending on whether electrical recombination or optical losses dominated. Effective minority carrier diffusion length under the majority carrier contacts was obtained by fitting of LBIC measurements. It was observed to have improved from 20.5 $\mu$m to 22.7–40.4 $\mu$m and up to 89.0 $\mu$m in the best case. Based on this, wider contact fingers and improved surface passivation at the electron contact is encouraged in the near future to achieve efficiencies $\geq$16%.

中文翻译：

---

通过光束感应电流对薄膜硅太阳能电池的表面钝化和激光烧制的分析

最近证明了玻璃上的液相结晶硅太阳能电池 15.1% 使用异质结叉指背接触电池架构和吸收体厚度为 14 $\mu$米。其中一个关键的发展是一种新方法，首先用 a-Si:H(i) 钝化电子接触指，然后局部激光烧制它们以保持低接触电阻。在这项工作中，高分辨率的光束感应电流测量 (LBIC) 用于分析这种方法。观察到电荷收集从0.13 ${\text{mAcm}}^{-2}$ 至 0.9 ${\text{mAcm}}^{-2}$在电子接触下增加了七倍。使用 520、642、932 和 1067 nm 波长的入射光，在包括晶界、位错缺陷、分流、无缺陷区域和激光烧制点在内的区域中映射外部量子效率。激光发射点中电荷收集的减少仅限于直径为 50-20 $\mu$m，取决于是电复合还是光损失占主导地位。多数载流子接触下的有效少数载流子扩散长度是通过拟合 LBIC 测量获得的。观察到从 20.5 $\mu$米到 22.7–40.4 $\mu$米和高达 89.0 $\mu$m 在最好的情况下。基于此，在不久的将来鼓励更宽的接触指和改进的电子接触表面钝化，以提高效率$\geq$16%。