Recombination via point defects and their complexes in solar silicon
Recombination via point defects and their complexes in solar silicon
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DOI：
10.1002/pssa.201200216
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发表时间：
2012-10
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影响因子：
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通讯作者：
A. Peaker;V. Markevich;B. Hamilton;G. Parada;A. Dudas;A. Pap;E. Don;B. Lim;J. Schmidt;L. Yu;Y. Yoon;G. Rozgonyi
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文献类型：
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作者：
A. Peaker;V. Markevich;B. Hamilton;G. Parada;A. Dudas;A. Pap;E. Don;B. Lim;J. Schmidt;L. Yu;Y. Yoon;G. Rozgonyi
电子级Czochralski和浮子区硅在生长状态下具有非常低的复合生成中心浓度（通常<1010 cm−3）。因此，在使用这种材料的集成电路技术中，电活性的无意杂质和结构缺陷很少被检测到。对廉价光伏电池的追求已经导致使用较少的纯硅，多晶材料，以及太阳能应用的低成本加工。以这种方式制造的细胞具有重要的外在重组机制。本文综述了单晶和多晶太阳硅中含有缺陷和杂质的复合。我们在这项工作中的主要技术是利用微波检测光导衰减和深能级瞬态光谱（DLTS）的变体进行复合寿命测绘测量。特别地，我们使用拉普拉斯DLTS来区分孤立的点缺陷，小沉淀配合物和装饰扩展缺陷。我们比较了太阳能硅中一些常见金属污染物的行为，以及它们对载流子寿命和电池效率的影响。最后，我们考虑了氢钝化在过渡金属污染物、晶界和位错方面的作用。我们的结论是，通过点缺陷的复合可能是重要的，但在大多数多晶材料中，主要的复合途径是通过晶粒内的装饰位错团簇，对晶界的整体复合贡献很小。
Electronic grade Czochralski and float zone silicon in the as grown state have a very low concentration of recombination generation centers (typically <1010 cm−3). Consequently, in integrated circuit technologies using such material, electrically active inadvertent impurities and structural defects are rarely detectable. The quest for cheap photovoltaic cells has led to the use of less pure silicon, multi‐crystalline material, and low cost processing for solar applications. Cells made in this way have significant extrinsic recombination mechanisms. In this paper we review recombination involving defects and impurities in single crystal and in multi‐crystalline solar silicon. Our main techniques for this work are recombination lifetime mapping measurements using microwave detected photoconductivity decay and variants of deep level transient spectroscopy (DLTS). In particular, we use Laplace DLTS to distinguish between isolated point defects, small precipitate complexes and decorated extended defects. We compare the behavior of some common metallic contaminants in solar silicon in relation to their effect on carrier lifetime and cell efficiency. Finally, we consider the role of hydrogen passivation in relation to transition metal contaminants, grain boundaries and dislocations. We conclude that recombination via point defects can be significant but in most multi‐crystalline material the dominant recombination path is via decorated dislocation clusters within grains with little contribution to the overall recombination from grain boundaries.