This work investigates the optical performance of a textured back surface reflector (BSR) produced by a maskless solution-based wet chemical etch in Al$_\text{0.3}$Ga$_\text{0.7}$As for a 1.1-$\mu$m-thick GaAs solar cell. Combining the maskless texture with the 94% reflective flat mirror resulted in a high haze in reflectance near 80% across the GaAs absorbing region. The increased diffuse reflectance from the maskless BSR provided a 19.7% increase in the integrated short-circuit current density from the base region of the 1.1-$\mu$m GaAs solar cell with the maskless BSR compared to the simulated 1.1-$\mu$m solar cell with no light trapping structures. Based on the principle concepts for the Fabry–Pérot etalon, the lifetime enhancement factor (LEF), defined as the extended photon lifetime in an optical cavity due to light trapping, was derived for the BSR devices. The LEF for the maskless BSR device was measured to be 4.3 times greater than the single-pass photon lifetime, agreeing with the high haze in reflectance and improved photoabsorption near the GaAs band edge. This value agrees with the F factor in the analytical propagation model that fits the experimental external quantum efficiency curves and justifies using the LEF to quantitatively represent the optical performance of light trapping structures in sub-$\mu$m thick solar cells.

中文翻译：

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具有无掩模背面反射器的薄砷化镓太阳能电池

这项工作研究了在铝中通过基于无掩模溶液的湿化学蚀刻产生的带纹理的背面反射器 (BSR) 的光学性能$_\text{0.3}$嘎$_\text{0.7}$至于 1.1-$\mu$m 厚的 GaAs 太阳能电池。将无掩模纹理与 94% 反射率平面镜相结合，导致整个 GaAs 吸收区域的反射率接近 80% 的高雾度。无掩模 BSR 增加的漫反射比 1.1- 基区的集成短路电流密度增加了 19.7%。$\mu$具有无掩模 BSR 的 m GaAs 太阳能电池与模拟的 1.1-$\mu$m 太阳能电池，没有光捕获结构。基于 Fabry-Pérot 标准具的原理概念，BSR 器件的寿命增强因子 (LEF) 被定义为由于光俘获而在光学腔中延长的光子寿命。经测量，无掩模 BSR 器件的 LEF 是单程光子寿命的 4.3 倍，这与 GaAs 带边缘附近反射率的高雾度和改进的光吸收相一致。该值与F 分析传播模型中的因子，该模型适合实验的外部量子效率曲线，并证明使用 LEF 定量表示亚光捕获结构的光学性能是合理的。$\mu$米厚的太阳能电池。