利用新型光捕捉結構提升矽薄膜太陽能電池元件效率

Efficiency Enhancement of a-Si Thin Film Solar Cell by New Light-Trapping Structure

郭鎮維(Chen-Wei Kuo)

指導教授 ： 莊賦祥

國立虎尾科技大學/電機資訊學院/光電與材料科技研究所/碩士(2010年)

摘要

本論文主要研究以超高頻電漿增強式化學氣相沉積系統(VHF- PECVD)研製高沉積速率10~15 Å/s之奈米結晶矽薄膜太陽電池，主要改善非晶矽懸吊鍵缺陷提升本質層薄膜穩定性。所製得之非晶矽薄膜以RAMAN、FTIR、UV-VIS、J-V、SEM等量測分析其性質。在250℃下沉積於ITO玻璃基板上，主要討論改變製程參數對氫化非晶矽本質層薄膜與太陽電池的電性及光學性質之影響。藉由調變氫氣稀釋比、製程壓力、VHF電漿功率、P/N摻雜濃度來探討矽薄膜特性包括沉積速率、光學特性、電特性，找出製程最佳參數應用於非晶矽薄膜太陽能電池元件。光封存結構主要探討利用新型光封存結構來達到高效率低成本的矽薄膜太陽能電池。第一部分，利用雷雕機雕刻不同圖樣於ITO電極以達到糙化效果。第二部份利用簡單的壓印法，將微結構膜仁塗佈UV膠壓印於太陽能電池受光面，此兩種結構皆讓光穿透進入元件後能有效增加光行走路徑與散射，進而提升元件效率。由結果得知，ITO糙化處理與受光面壓印微結構薄膜，元件效率分別由4.59 %提升至5.19 %與5.99 %。最後將兩種結構結合，元件效率提升至6.29 %，效率提升幅度為37 %。背電極層加入TCO層可解決金屬與矽之間的附著性差問題，元件效率由4.59%提升至6.17%，將此最佳結構壓印V-type微結構抗反射膜，效率由6.17%至8.09%。最後研究以可撓式基板或轉貼技術製作可撓式太陽能電池，提升其應用價值。

關鍵字

矽薄膜太陽能電池 ； 超高頻電漿化學氣相沉積系統 ； 非晶矽 ； 奈米結晶矽 ； 光捕捉結構

並列摘要

In this study, we have developed a-Si:H thin film solar cells (P-I-N) by Very High Frequency Plasma Enhanced Chemical Vapor Deposition (VHF PECVD) at high rate (10-15 Å/s) are investigated. We analyed the thin film properties by UV-VIS、SEM、FTIR、Raman and J-V measure. The a-Si:H solar cells with the best performance are obtained by change VHF power, pressure, hydrogen dilution ratio(SC %),P- and N-type doping.
We study produced different light trapping structures to enhance the component efficiency for amorphous silicon thin film solar cells. The first part used laser engraving to produce different patterns on the ITO electrode to obtain a roughening effect. The second part used a simple transfer-print technique to print a micro structure on a UV glue layer which was spin coated onto the component’s illuminated face of the solar cell. As light penetrated through the component, the transfer-printed anti-reflective film and roughened ITO electrode effectively increased the optical path and scattering of light, which further enhanced the power conversion efficiency of the solar cell. When these easy-produced light trapping structures are applied to solar cells, they can effectively enhance the solar cell power conversion efficiency and reduce production costs. Results showed that the ITO surface was laser engraved with a straight line pattern, the efficiency enhanced from 4.59 to 5.19 %.In the anti-reflective film research, the structure was a V-type film, the power conversion efficiency enhanced from 4.59 to 5.99 %. When combine V-type anti-reflection with square-type of TCO structures, the power conversion efficiency of a-Si solar cell can be increased 4.59 to 6.29 %. And we depostie ITO thin film on back contact electrode to improve metal and silicon thin film contact. Results showed this structrure, the power conversion efficiency enhanced from 4.59 to 6.17 %, and use best profermance anti-reflection structure to 8.09 %. Finally, we fabricate flexible solar cells on flexible substrates or lift off method to increase practical applications.

並列關鍵字

thin film solar cells ； VHF-PECVD ； Amorphous silicon ； Nano-crystalline ； Light trapping structure

參考文獻

1. 黃信雄；「氣候變化綱要公約」；太陽能學刊 第2卷第一期, 1997.

2. J. C. Yang, Prog. Photovolt. Res. Appl.6 pp.181-186 (1998).

3. H. F. Sterling, R. C. G Swann, “Chemical vapor deposition promoted by r.f. discharge, solid-state Electron”, 8(8), 653 (1965).

4. W. E Spear, P. G Le Comber, “Substitutional doping of amorphous silicon”, Solid State Communications, Vol 17, pp.1193-1196 (1975).

5. W. E. Spear, P. L. Comber, “Electronic properties of substitutionally doped amorphous Si and Ge”, Philosophical Magazine, Vol 33, pp.935-949 (1976).