Effective method to extract optical bandgaps in Si nanowire arrays.
Effective method to extract optical bandgaps in Si nanowire arrays.
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DOI：
10.1364/ol.36.002677
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发表时间：
2011-07
期刊：
影响因子：
3.6
通讯作者：
Jin-Young Jung;Keya Zhou;Han-Don Um;Zhongyi Guo;Sang-won Jee;Kwang-Tae Park;Jung‐Ho Lee
中科院分区：
文献类型：
--
作者：
Jin-Young Jung;Keya Zhou;Han-Don Um;Zhongyi Guo;Sang-won Jee;Kwang-Tae Park;Jung‐Ho Lee
本文介绍了一种利用独立式 SiNW 阵列的反射光谱提取硅纳米线 (SiNW) 阵列光学带隙的简单方法。在固定的纳米线直径下，三种不同的线长度可重复地在其反射率曲线图中形成交叉点。交叉点波长对应于光学带隙，由经典 Tauc 模型验证。 SiNW 阵列（平均直径为 112 nm）的光学带隙经测量约为 1.19 eV，大于体硅的约 1.08 eV 带隙。进一步将线直径减小至 68 nm，导致带隙增加至约 1.24 eV，这更接近单结光伏器件实现最高转换效率所需的最佳带隙（约 1.40 eV）。我们的方法表明，多结串联结构可以通过控制 SiNW 阵列的直径来实现。
A simple method to extract the optical bandgap of Si nanowire (SiNW) arrays that utilizes the reflection spectra of freestanding SiNW arrays is presented in this Letter. At a fixed nanowire diameter, three different wire lengths reproducibly formed a cross point in their reflectance curve plots. The cross point wavelength corresponded to the optical bandgap, as verified by the classical Tauc's model. The optical bandgap of the SiNW arrays (112 nm in average diameter) was measured to be ~1.19 eV, which is larger than the ~1.08 eV bandgap of bulk Si. Further decreasing the wire diameter to 68 nm caused an increase of the bandgap to ~1.24 eV, which is closer to the optimal bandgap (~1.40 eV) required to achieve the highest conversion efficiency in single-junction photovoltaic devices. Our method suggests that the multijunction tandem structure can be realized via control of the diameter of SiNW arrays.