Nanometre-scale optical property fluctuations in Cu2ZnSnS4 revealed by low temperature cathodoluminescence
Nanometre-scale optical property fluctuations in Cu2ZnSnS4 revealed by low temperature cathodoluminescence
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DOI：
10.1016/j.solmat.2017.08.028
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发表时间：
2018
影响因子：
6.9
通讯作者：
B. Mendis;A. Taylor;M. Guennou;D. Berg;M. Arasimowicz;Shafaat Ahmed;H. Deligianni;P. Dale
中科院分区：
文献类型：
--
作者：
B. Mendis;A. Taylor;M. Guennou;D. Berg;M. Arasimowicz;Shafaat Ahmed;H. Deligianni;P. Dale
能带拖尾是目前限制Cu 2 ZnSnS 4（CZTS）光伏器件的大的开路电压（Voc）不足的主要促成因素。它发生在高度掺杂、高度补偿的半导体中，并产生不均匀的电子能带结构。在这里，我们报告的空间分辨波动CZTS的光学性质，使用低温阴极射线发光（CL）在扫描电子显微镜（SEM）。主成分分析揭示了三个CL峰，其相对强度在尺寸约100 nm的区域内变化。不均匀的光学性质是由于组成的变化还是由于恒定组成下的结构有序-无序，目前尚不清楚。在SEM中用能量色散X射线（EDX）分析测量组成，并用显微拉曼映射进行排序，显示CZTS在两种技术的空间分辨率（估计分别为约0.4 µm和1.1 µm）和灵敏度内是均匀的。CL结果与CZTS中存在条带拖尾一致。
Band tailing is a major contributing factor to the large open circuit voltage (Voc) deficit that is currently limiting Cu2ZnSnS4(CZTS) photovoltaic devices. It occurs in highly doped, highly compensated semiconductors and gives rise to a non-uniform electronic band structure. Here we report spatially resolved fluctuations in CZTS optical properties using low temperature cathodoluminescence (CL) in a scanning electron microscope (SEM). Principal component analysis reveals three CL peaks whose relative intensity vary across domains ~ 100 nm in size. It is not known whether the non-uniform optical properties are due to changes in composition or due to structural order-disorder at constant composition. Measurement of composition with energy dispersive X-ray (EDX) analysis in an SEM and ordering with Micro-Raman mapping revealed CZTS to be uniform within the spatial resolution (estimated at ~ 0.4 µm and 1.1 µm respectively) and sensitivity of the two techniques. The CL results are consistent with the presence of band tailing in CZTS.