Qin Xuefei, Wu Yonggang, Zhang Zongyi, Xia Zihuan, Zhou Jian, Zhu Jianwei
Appl Opt. 2019 Feb 1;58(4):1152-1157. doi: 10.1364/AO.58.001152.
Semiconducting nanohole arrays have been considered as a promising candidate for high-efficiency solar cells. In this paper, the optical absorption property of randomly rotated elliptical nanohole arrays consisting of 1×1, 2×2, and 4×4 cells has been investigated. It is found that the average ultimate efficiency of the arrays increases with the increase of the size of the supercell. The 4×4 array has the highest ultimate efficiency, and the efficiency of the 4×4 array is less sensitive to the parameters of the random rotation angle than that of the 1×1 and 2×2 arrays. The comparison of absorption spectra of the three arrays shows that the number of absorption peaks of the 1×1 array is the least, but the peak is the highest and narrowest, and that of the 4×4 array is the most, but the peak is the lowest and broadest. The spatial Fourier spectroscopy analysis of the array shows that the 4×4 arrays have the most Fourier spectrum components and the largest absorption mode density. The enhancement of optical absorption of the 4×4 array is attributed to the folding of energy bands, the increase of the energy density of states caused by large supercells, and the overcoupling between incident light and Bloch resonant modes in the structure. The improved stability of the ultimate efficiency of the 4×4 arrays is because the distribution of the energy density of states of the 4×4 arrays with different random parameters tends to be the same, which leads to almost the same absorption efficiency of the different 4×4 arrays.
半导体纳米孔阵列被认为是高效太阳能电池的一个有前途的候选材料。本文研究了由1×1、2×2和4×4单元组成的随机旋转椭圆纳米孔阵列的光吸收特性。发现阵列的平均极限效率随着超胞尺寸的增加而提高。4×4阵列具有最高的极限效率，并且4×4阵列的效率对随机旋转角度参数的敏感度低于1×1和2×2阵列。三种阵列吸收光谱的比较表明，1×1阵列的吸收峰数量最少，但峰值最高且最窄，而4×4阵列的吸收峰数量最多，但峰值最低且最宽。阵列的空间傅里叶光谱分析表明，4×4阵列具有最多的傅里叶光谱分量和最大的吸收模式密度。4×4阵列光吸收的增强归因于能带折叠、大超胞导致的态密度能量增加以及结构中入射光与布洛赫共振模式之间的过耦合。4×4阵列极限效率稳定性的提高是因为具有不同随机参数的4×4阵列的态密度能量分布趋于相同，这导致不同的4×4阵列具有几乎相同的吸收效率。
