Optical Absorption Enhancement in Amorphous Silicon Nanowire and Nanocone Arrays
Optical Absorption Enhancement in Amorphous Silicon Nanowire and Nanocone Arrays
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DOI：
10.1021/nl802886y
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发表时间：
2009-01-01
期刊：
影响因子：
10.8
通讯作者：
Cui, Yi
中科院分区：
文献类型：
--
作者：
Zhu, Jia;Yu, Zongfu;Cui, Yi
氢化非晶硅（a-Si：H）是一种重要的太阳能电池材料。在这里，我们展示了a-Si：H纳米线（NW）和纳米锥（NC）的制造，使用一个易于扩展和IC兼容的过程。我们还研究了这些纳米结构的光学性质。这些a-Si：H纳米结构由于抑制反射而在大范围的波长和入射角上显示出极大增强的吸收。a-Si：H NC阵列的增强效果特别强，其通过逐渐减小有效折射率在a-Si：H和空气之间提供近乎完美的阻抗匹配。对于a-Si：H NC阵列，超过90%的光在高达60 °的入射角下被吸收，这明显优于NW阵列（70%）和薄膜（45%）。此外，NC阵列在a-Si：H带隙边缘的吸收率为88%，远高于NW阵列（70%）和薄膜（53%）。我们的实验数据与模拟吻合得很好。a-Si：H纳米锥具有吸收层和吸收层的双重功能，为提高太阳能电池的能量转换效率提供了一种很有前途的方法。
Hydrogenated amorphous Si (a-Si:H) is an important solar cell material. Here we demonstrate the fabrication of a-Si:H nanowires (NWs) and nanocones (NCs), using an easily scalable and IC-compatible process. We also investigate the optical properties of these nanostructures. These a-Si:H nanostructures display greatly enhanced absorption over a large range of wavelengths and angles of incidence, due to suppressed reflection. The enhancement effect is particularly strong for a-Si:H NC arrays, which provide nearly perfect impedance matching between a-Si:H and air through a gradual reduction of the effective refractive index. More than 90% of light is absorbed at angles of incidence up to 60 for a-Si:H NC arrays, which is significantly better than NW arrays (70%) and thin films (45%). In addition, the absorption of NC arrays is 88% at the band gap edge of a-Si:H, which is much higher than NW arrays (70%) and thin films (53%). Our experimental data agree very well with simulation. The a-Si:H nanocones function as both absorber and antireflection layers, which offer a promising approach to enhance the solar cell energy conversion efficiency.