次波長仿生結構對太陽能電池材料表面反射率之影響

The Influences of Subwavelength Biomimetic Structures on the Surface Reflection of Photovoltaic materials

周彥宇(Yen-Yu Chou)

指導教授 ： 李有璋

中原大學/工學院/機械工程研究所/碩士(2011年)

https://doi.org/10.6840/cycu201100886

摘要

當陽光入射於太陽能電池表面時，便會因為空氣與材料間折射率的差異而產生菲涅爾損失，不但導致太陽能電池的光電轉換效率不理想，也使得發電成本提高，阻礙了太陽能電池在日常生活中的應用。次波長結構由於具有對應寬波長且不同入射角的抗反射特性，目前已經逐漸取代傳統的抗反射膜。嚴格耦合波分析理論(rigorous couple-wave analysis, RCWA）是以電磁學中的馬克斯威爾方程式為基礎，在不做任何假設的條件下，對次波長結構中的繞射行為進行求解。因此本論文以RCWA理論針對次波長結構的抗反射機制作一系列的探討，分析結構圖形、間距、直徑、高度、折射率等參數對太陽能電池材料表面反射率的影響。結果顯示，當結構折射率與太陽能電池材料相同時，越小的結構間距及越高的結構高度，可以有效降低材料表面的反射率，在結構直徑、高度、間距為700 nm、700 nm、0 nm的情況下，矽材料與砷化鎵表面於光譜範圍300 nm～1200 nm的平均反射率分別為0.55 %、0.64 %。除了以數值分析模擬次波長結構外，本實驗也利用奈米球微影技術搭配乾蝕刻製程製作出次波長結構，並將量測的反射率與模擬結果做比較，驗證模擬模型的正確性，希望模擬結果也可以作為日後實際應用於太陽能電池上的參考依據。

關鍵字

抗反射 ； 嚴格耦合波分析理論 ； 次波長仿生結構結構 ； 太陽能電池

並列摘要

When sunlight incident on the surface of solar cell, Fresnel reflection occurs at the air-material interface due to the refractive index difference across the interface. Reflection does not only lead to less photoelectric conversion efficiency but also increase power generation costs, which hinder widespread use of solar cell.
Thin films are normally used for anti-reflection coating, but the conventional anti-reflective films are gradually replaced by sub-wavelength structures since their good anti-reflective properties of broadband wavelength and wide incident angles. This thesis used RCWA theory to study the anti-reflective mechanism of sub-wavelength structure on the surface, and numerical simulation was used to analyze the influences of structural profile、spacing、diameter、height and refractive index on the surface reflectance of the solar cell material. The results showed smaller structural spacing and higher structural height contribute to less reflectance when the refractive induces of sub-wavelength structures are same as of the solar cell material. In this study, the average reflectance of silicon and gallium arsenide is 0.55% and 0.64% when the diameter、height and spacing are 700 nm、700nm and 0 nm respectively.
Nano-sphere lithography with dry etching process were used to the fabricate sub-wavelength structures. The experiments are analyzed to verify correctness of the simulation model.

並列關鍵字

Subwavelength biomimetic structures ； RCWA ； anti-reflection ； solar cell

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