Diffusion barriers for CIGS solar cells on metallic substrates
Diffusion barriers for CIGS solar cells on metallic substrates
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DOI：
10.1016/s0040-6090(03)00259-1
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发表时间：
2003-05-01
期刊：
影响因子：
2.1
通讯作者：
Powalla, M
中科院分区：
文献类型：
--
作者：
Herz, K;Eicke, A;Powalla, M
通过射频溅射从钛、Kovar(R) 和铬钢金属箔上的陶瓷靶材上沉积 1-3 μm 的 Al2O3 层作为扩散阻挡层。使用 CIGS 共蒸发工艺，在 T 大于或等于 550 摄氏度的条件下，将基于 Cu(In,Ga)Se-2 (CIGS) 的薄膜太阳能电池沉积到这些基板上。 0.25 cm(2) 的 CIGS 太阳能电池在没有任何 Na 掺杂的情况下实现了约 10-11% 的效率。如果没有阻挡层，除了钛基板之外，电池效率会被限制在显着较低的值。效率值降低主要归因于填充因子的降低，其次是开路电压的降低。通过同步二次离子质谱和溅射中性质谱深度分析进行研究，不同的太阳能电池效率可能与从基板扩散进入 CIGS 层的杂质数量相关。在没有扩散势垒的情况下，在铬钢上的 CIGS 层中检测到了数百 ppm 的 Fe 和 Cr 浓度。 Kovar(R) 和 Ti 基材中的 Fe、Ni、Co 和 Ti 浓度要小得多，表明扩散减少。与没有阻挡层的系统相比，使用 Al2O3 阻挡层时，CIGS 中 Fe 和 Cr 的浓度与阻挡层厚度成比例地降低了 100 倍。 (C) 2003 Elsevier Science B.V. 保留所有权利。
Al2O3 layers of 1-3 mum were deposited as diffusion barriers by RF sputtering from a ceramic target on metal foils of Ti, Kovar(R) and Cr steel. Cu(In,Ga)Se-2 (CIGS)-based thin-film solar cells were deposited onto these substrates using a co-evaporation process for CIGS at Tgreater than or equal to550 degreesC. CIGS solar cells of 0.25 cm(2) achieved efficiencies of approximately 10-11% without any Na doping. Without barriers, the cell efficiencies were limited to significantly lower values except for Ti substrates. The reduced efficiency values can be attributed mainly to a reduction in fill factors, and secondly, to reduced open-circuit voltages. The different solar cell efficiencies can be correlated with the amount of impurities entering the CIGS layer by diffusion from the substrates, as investigated by simultaneous secondary ion mass spectrometry and sputtered neutral mass spectrometry depth profiling. Without diffusion barriers, Fe and Cr concentrations of several hundred ppm were detected in CIGS layers on Cr steel. Fe, Ni, Co and Ti concentrations from Kovar(R) and Ti substrates were much smaller, indicating a reduced diffusion. Using Al2O3 barriers, the concentrations of Fe and Cr in CIGS are reduced proportionally to the barrier thickness by up to a factor of 100 when compared to systems without barriers. (C) 2003 Elsevier Science B.V. All rights reserved.