III-V 族多接面太陽電池表面光柵收光增益的研究

Abstract

本論文主要在於研究如何在III-V族太陽能電池表面製作光柵以增廣可利用的太陽光譜頻寬與大角度的吸收。首先我們利用一套嚴格耦合波的數學方法來設計在AM1.5下太陽光譜的最佳光柵結構，接著利用電子微影技術將光柵生長在InGaP/GaAs/Ge III-V族太陽電池表面；最後進行變角度量測。 量測結果發現，擁有光柵的太陽能電池普遍擁有較高轉換效率，尤其在大角度上的表現，與理論預測的趨勢大致相同。雖然光的吸收率與能量轉換效率並沒有直接關係，但至少我們可以證實擁有光柵的太陽電池卻實在整體效率與大角度的吸收都比只生長抗反射層的電池來得高。故此，如果我們能夠利用低成本的方式大量複製此光柵在太陽能電池上，對於光跡追蹤與其他地面發電運用都有一定的貢獻。

In this dissert, we want to study the improvement of light trapping mechanism due to grating grown its surface in order to achieve higher efficiency at higher incidence. Firstly, we adopt a numerically stable mathematical calculation called rigorous coupled-wave analysis, RCWA, to optimize the profile of grating structure. Then we realize it onto real InGaP/GaAs/Ge III-V MJ solar cell. Lastly, the efficiencies will be measured under standard AM1.5G solar spectrum at various incidences. In general, the experiment results of samples with grating present higher efficiency than those without. Better performance can also be achieved at larger oblique incidence. Surprisingly, the efficiencies follow the trend of transmittance rate as RCWA has estimated. Although it is quite complicated to judge the relation categorically; we can still attribute the improvements of increasing photon penetrating to grating mechanisms. As a result, if we can find another more effective and less costly way during fabrication process, the contribution of this light trapping structure could be widely extended due to the light tracking system and terrestrial applications have become more prosperous in recent years.