Ziang Xie, Wei Wang, Laixiang Qin, Wanjin Xu, Qin G G
State Key Lab for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China.
Opt Express. 2013 Jul 29;21(15):18043-52. doi: 10.1364/OE.21.018043.
The optical absorption properties of a-Si:H have acquired much attention in solar cell(SC) research. In this paper, we studied enhancement of light absorption in the a-Si:H(10%H) SCs with thicknesses from 31.25nm to 2μm and with nano textures of the column-shaped nanohole (CLNH) array and of the cone-shaped nanohole (CNNH) array, via the Finite Difference Time Domain (FDTD) simulation. For a given type of nano texture and film thickness, d, the ultimate efficiency, the ideal efficiency without considering carrier combinations, is optimized over array period, p, and filling fraction, f, and is defined as the optimized ultimate efficiency, η(0). The simulation results demonstrated that: even for the CLNH textured a-Si:H(10%H) SCs as thin as 62.5 nm,η(0) is 19.7%. When the a-Si:H(10%H) SC is thinner than a critical depth of about 250nm, the CLNH texture is more efficient than the CNNH texture, and vice versa. When the thicknesses of SCs are very thin, especially smaller than 100nm, the efficiencies of the a-Si:H(10%H) SCs are evidently higher than those of the c-Si SCs. For example, in the CLNH arrays, when d = 62.5nm, η(0)for the a-Si:H(10%H) SCs is higher than the c-Si SCs by a factor of approximate 2.3.
非晶硅氢化薄膜（a-Si:H）的光吸收特性在太阳能电池（SC）研究中备受关注。本文通过时域有限差分（FDTD）模拟，研究了厚度从31.25nm至2μm、具有柱状纳米孔（CLNH）阵列和锥状纳米孔（CNNH）阵列纳米纹理的a-Si:H（10%H）太阳能电池中的光吸收增强情况。对于给定类型的纳米纹理和薄膜厚度d，在不考虑载流子复合的理想情况下，通过优化阵列周期p和填充率f得到的极限效率被定义为优化极限效率η(0)。模拟结果表明：即使对于厚度仅为62.5nm的CLNH纹理化a-Si:H（10%H）太阳能电池，η(0)也可达19.7%。当a-Si:H（10%H）太阳能电池的厚度小于约250nm的临界深度时，CLNH纹理比CNNH纹理更有效，反之亦然。当太阳能电池的厚度非常薄，特别是小于100nm时，a-Si:H（10%H）太阳能电池的效率明显高于晶体硅（c-Si）太阳能电池。例如，在CLNH阵列中，当d = 62.5nm时，a-Si:H（10%H）太阳能电池的η(0)比c-Si太阳能电池高出约2.3倍。
