Abstract. Traditional Cu ( InGa ) Se2 (CIGS) solar cells consist of an Mo bottom contact, p-type CIGS absorber layer, n-type CdS buffer layer, and ZnO window layer including a very thin intrinsic ZnO layer topped with an Al-doped ZnO transparent conducting oxide layer that was simulated by an Silvaco technology computer aided design simulator. The thickness of the layers and other parameters were limited to the values reported in the literature. The simulator was examined to affirm its functionality, and a step-by-step method was applied to optimize the baseline structure. The first modification was the substitution of the conventional CdS buffer layer with a nontoxic n-type ZnO buffer layer. The substituted ZnO buffer layer showed an effective band alignment and led to a remarkable improvement in cell performance. The second modification was the inclusion of different antireflective coatings, such as Al2O3, MgO, SnO2, and CdO, to enhance light trapping. Among them, CdO caused the highest efficiency. The optimization process was followed by replacing a very-thin (750 nm) CIGS layer containing three sublayers with dual-graded Ga contents. A trapezoidal gradient profile was tested and showed a significantly increased internal electric field, which assisted in raising the efficiency of the device. The last simulation concluded that the efficiency of a CIGS solar cell was 19.21% and the efficiency related to the baseline structure was enhanced by 36.24%.

中文翻译：

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超薄渐变Cu(InGa)Se2太阳能电池通过修改基本结构和增加抗反射层提高性能

摘要。传统的 Cu ( InGa ) Se2 (CIGS) 太阳能电池由 Mo 底部触点、p 型 CIGS 吸收层、n 型 CdS 缓冲层和 ZnO 窗口层组成，其中包括非常薄的本征 ZnO 层，顶部是 Al 掺杂的 ZnO由 Silvaco 技术计算机辅助设计模拟器模拟的透明导电氧化物层。层的厚度和其他参数仅限于文献中报告的值。检查模拟器以确认其功能，并应用逐步方法来优化基线结构。第一个修改是用无毒的 n 型 ZnO 缓冲层替代传统的 CdS 缓冲层。取代的 ZnO 缓冲层显示出有效的能带排列，并显着提高了电池性能。第二个修改是包含不同的抗反射涂层，如 Al2O3、MgO、SnO2 和 CdO，以增强光捕获。其中，CdO引起的效率最高。优化过程之后是用双梯度 Ga 含量替换包含三个子层的非常薄 (750 nm) 的 CIGS 层。梯形梯度分布被测试并显示出显着增加的内部电场，这有助于提高器件的效率。最后的模拟得出结论，CIGS 太阳能电池的效率为 19.21%，与基线结构相关的效率提高了 36.24%。优化过程之后是用双梯度 Ga 含量替换包含三个子层的非常薄 (750 nm) 的 CIGS 层。梯形梯度分布被测试并显示出显着增加的内部电场，这有助于提高器件的效率。最后的模拟得出结论，CIGS 太阳能电池的效率为 19.21%，与基线结构相关的效率提高了 36.24%。优化过程之后是用双梯度 Ga 含量替换包含三个子层的非常薄 (750 nm) 的 CIGS 层。梯形梯度分布被测试并显示出显着增加的内部电场，这有助于提高器件的效率。最后的模拟得出结论，CIGS 太阳能电池的效率为 19.21%，与基线结构相关的效率提高了 36.24%。