Symmetry-breaking nanostructures on crystalline silicon for enhanced light trapping in thin film solar cells
Symmetry-breaking nanostructures on crystalline silicon for enhanced light trapping in thin film solar cells
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DOI：
10.1364/oe.24.0a1586
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发表时间：
2016-12-26
期刊：
影响因子：
3.8
通讯作者：
Han, Sang Eon
中科院分区：
文献类型：
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作者：
Han, Seok Jun;Ghosh, Swapnadip;Han, Sang Eon
我们介绍了一种新的方法，系统地打破对称性的周期性纳米结构的晶体硅表面。我们的重点是倒置纳米金字塔阵列与规定的对称性。纳米角锥体的排列和对称性由蚀刻掩模设计及其相对于Si（001）衬底的[110]取向的旋转确定。这种方法消除了使用昂贵的切割硅片的需要。我们还利用低成本，可制造，湿法蚀刻步骤来制造纳米锥。我们的实验和计算模型表明，对称性破缺可以提高薄膜硅太阳能电池的光伏效率。对于10微米厚的有源层，效率从27.0%提高到27.9%，通过在宽的太阳光谱上增强光捕获。我们的计算进一步表明，这种改善将增加从28.1%到30.0%的情况下，20微米厚的有源层，当纳米锥之间的未蚀刻区域最小化与过蚀刻。除了直接的好处，太阳能photochemics，我们的对称性破缺的方法提供了一个有用的实验平台，广泛研究对称性破缺光谱调谐光吸收和发射的影响。(C)2016美国光学学会
We introduce a new approach to systematically break the symmetry in periodic nanostructures on a crystalline silicon surface. Our focus is inverted nanopyramid arrays with a prescribed symmetry. The arrangement and symmetry of nanopyramids are determined by etch mask design and its rotation with respect to the [110] orientation of the Si(001) substrate. This approach eliminates the need for using expensive off-cut silicon wafers. We also make use of low-cost, manufacturable, wet etching steps to fabricate the nanopyramids. Our experiment and computational modeling demonstrate that the symmetry breaking can increase the photovoltaic efficiency in thin-film silicon solar cells. For a 10-micron-thick active layer, the efficiency improves from 27.0 to 27.9% by enhanced light trapping over the broad sunlight spectrum. Our computation further reveals that this improvement would increase from 28.1 to 30.0% in the case of a 20-micron-thick active layer, when the unetched area between nanopyramids is minimized with over-etching. In addition to the immediate benefit to solar photovoltaics, our method of symmetry breaking provides a useful experimental platform to broadly study the effect of symmetry breaking on spectrally tuned light absorption and emission. (C) 2016 Optical Society of America