脈衝調變RF電漿對氫化非晶矽太陽能電池本質層薄膜的價態與穩定性之影響

Influence of modulated RF silane plasma on the gap states and stability of the intrinsic layer of a-Si:H Solar Cell

施智仁(Jhih-ren Shih)

指導教授 ： 楊木榮

大同大學/工程學院/材料工程學系所/碩士(2007年)

摘要

氫化非晶矽(a-Si:H)薄膜為一短程有序的結構，被應用於半導体和薄膜太陽電池，具有製程簡單、成本低廉等特性，然而由於結構缺陷較多，非晶矽太陽能電池轉換效率較低於結晶矽太陽能電池。如何有效改善轉換效率成為當前重要的研究議題。
本實驗利用化學氣相沉積法(PECVD)在200 ℃下分別於康寧1737F玻璃、矽晶片與片電阻＜15 Ω的ITO玻璃基板上製備本質層薄膜與太陽電池，太陽電池結構為glass/ITO/pii'n/Al。本實驗主要討論改變製程參數(脈波調變頻率)對氫化非晶矽本質層薄膜及太陽電池的電性及光學性質之影響。所製得之本質層薄膜以RAMAN、FTIR、AFM、SE、UV-VIS、I-V等量測分析其性質。對本質層薄膜的研究結果顯示，藉由改變脈波調變頻率可有效減少薄膜中的氫氣總含量，減少SiH2鍵結的生成，改善微結構變數，提升光電流與光暗電導比。由於本質層薄膜品質的改善，太陽電池的短路電流提高，轉換效率提升，且其理想因子(Ideal Factor)值較低，為一較理想的二極體元件。

關鍵字

太陽能電池

並列摘要

Amorphous silicon (a-Si) thin film with a short range order has been extensively used in semiconductors and thin film solar cells owing to its simple manipulation processes and low cost. However, the transition efficiency of the amorphous silicon solar cell is much lower than the crystalline silicon solar cell due to the much higher structure defects. It has been an important issue on how to improve the transition efficiency of amorphous silicon solar cells effectively.
Hydrogenated amorphous silicon (a-Si:H) intrinsic thin films and solar cells were prepared by radio-frequency plasma enhanced chemical vapor deposition (PECVD) on Corning 1737F glasses, silicon wafers and ITO glasses respectively. The structure of the solar cell is glass/ITO/pii'n/Al. Different pulse modulation plasma manipulation processes were employed in this study. The relationships among the fabrication parameters( modulation frequency) of intrinsic layer, the electrical performance and optical properties of solar cells were investigated. The associated experiments involved RAMAN, FTIR, AFM, SE, UV-VIS, and I-V measurements. It can seen that the microstructure fraction ratio, photon current and photon to dark conductivity ratio were improved by different pulse modulate frequency due to the decrease of the total hydrogen content and SiH2 bonding in intrinsic thin films. The improvement of the intrinsic layer properties (i.e., less defects) increases the short current and transition efficiency and make the solar cells as ideal diodes with lower ideal factors.

並列關鍵字

solar cell

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