利用嵌入式奈米晶矽之量子效應進行高效率薄膜太陽能電池技術研究

Quantum confinement effect in embedded nano-crystalline silicon for high efficiency thin film solar cells

許嘉巡(Chia-Hsun Hsu)

指導教授 ： 沈幼敏

元智大學/工程學院/先進能源碩士學位學程/碩士(2011年)

https://doi.org/10.6838/YZU.2011.00055

摘要

本論文研究主要為將尺寸為3~5 nm之奈米晶矽嵌入P型非晶矽材料中，藉由奈米晶矽特有之量子侷限效應（Quantum confinement effect），將p型非晶矽材料能隙從1.75 eV提高到1.9 eV以上，以形成異質接面（Hetero-junction）薄膜太陽能電池結構。該電池結構開路電壓(VOC)可由目前非晶矽薄膜之0.8 V往上提升，使得電池效率提高到大於9%以上。未來亦可結合微晶矽製程技術，開發奈米晶矽/微晶矽堆疊式薄膜太陽能電池結構，將電池效率提升至11%。此外利用基板上TCO微結構來增加光捕捉(light trapping)效率，可進一步再提昇奈米晶矽/微晶矽堆疊式薄膜太陽能電池光電轉換效率。
另外，由於奈米晶矽或微晶矽薄膜沉積時需要大量氫原子參與反應，而超高頻率(VHF)之電漿輔助化學氣相沉積系統或電子迴旋共振系統(ECR-CVD，頻率為2.45 GHz)氣體解離率佳，非常適合用來沉積微晶矽或奈米晶矽薄膜，故本研究另一項重點為進行ECR-CVD矽鍍膜驗證，嘗試將PECVD製程技術轉移至ECR-CVD上，並由薄膜量測結果提出分析與建議。

關鍵字

奈米晶矽 ； 量子侷限效應 ； 電子迴旋共振

並列摘要

In this study, the silicon nano-crystals were embedded into amorphous silicon thin films, leading to an increase in optical band gap due to the quantum confinement effect. A nc-Si:H film with the band gap of 1.95 eV was obtained by VHF (27.12 MHz) PECVD system and was used as a window layer for p-i-n a-Si:H thin film solar cells. The hetero-junction, p-layer nc-Si:H/i-layer a-Si:H, solar cell demonstrated an open-circuit voltage (Voc) of 0.88 V and a conversion efficiency of greater than 9%. This kind of cell structure has great potential for the development of the a-Si/uc-Si tandem cell and the conversion efficiency is expected to be 11%.
In addition, ECR-CVD (microwave frequency: 2.45 GHz) technique is powerful for the deposition of silicon films with high deposition rate. In this study, we attempted to use the system to deposit silicon films. The PECVD process experiences were helpful to give reasonable deposition parameters for ECR-CVD. Finally, we give some suggestions base on the measurement results of the film deposited by ECR-CVD.

並列關鍵字

nano-crystalline silicon ； quantum confinement effect ； ECR-CVD

參考文獻

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