The optical properties of Λ-graded indium gallium nitride (InGaN) solar cells are studied. Graded InGaN well structures with the indium composition increasing to xmax and then decreasing in a Λ-shaped pattern have been designed. Through polarization doping, this naturally creates alternating p- and n-type regions. Separate structures are designed by varying the indium alloy profile from GaN to maximum indium concentrations ranging from 20% to 90%, while maintaining a constant overall structure thickness of 100 nm. The solar cell parameters under fully strained and relaxed conditions are considered. The results show that a maximum efficiency of ≅5.5 % under fully strained condition occurs for xmax = 60 % . Solar cell efficiency under relaxed conditions increases to a maximum of 8.3% for xmax = 90 % . Vegard’s law predicts the bandgap under relaxed conditions, whereas a Vegard-like law is empirically determined from the output of nextnano™ for varying indium compositions to calculate the solar cell parameters under strain.

中文翻译：

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Λ 级 InxGa1−xN 太阳能电池的建模：应变和松弛特征的比较

研究了Λ梯度氮化铟镓（InGaN）太阳能电池的光学特性。已经设计了梯度的 InGaN 阱结构，其铟成分增加到 xmax 然后以 Λ 形图案减小。通过极化掺杂，这自然会产生交替的 p 型和 n 型区域。通过改变从 GaN 到 20% 到 90% 范围内的最大铟浓度的铟合金分布来设计单独的结构，同时保持 100 nm 的恒定整体结构厚度。考虑完全应变和松弛条件下的太阳能电池参数。结果表明，当xmax = 60%时，在完全应变条件下的最大效率为≅5.5%。xmax = 90 % 时，松弛条件下的太阳能电池效率最高可增加到 8.3%。