微晶矽薄膜太陽能電池製作及分析

Fabrication and Characterization of the Microcrystalline Silicon Thin Film Solar Cell

陳韋廷(Wei-Ting Chen)

指導教授 ： 孫台平

國立暨南國際大學/科技學院/生物醫學科技研究所/碩士(2009年)

https://doi.org/10.6837/NCNU.2009.00218

摘要

本論文使用電漿增強式化學氣相沉積系統[Very High Frequency (27.12MHz)-Plasma Enhanced Chemical Vapor Deposition, VHF-PECVD] 沉積微結晶矽薄膜及製作微結晶矽薄膜太陽能電池。並探討當改變氫氣量、電極與基板距離(E/S)及RF功率時，對薄膜的結晶性質之影響。
在固定的E/S、B2H6流量及RF功率之下，改變P層的SiH4與氫氣流量比，從SC[H2/(SiH4+H2)] =98.5 %改變至99 %時，可得到較高的效率值，開路電壓(Voc)明顯的提高。當固定SC=98.5 % 或SC=99 % 時，開路電壓(Voc) 和填充因子(FF)會隨P層厚度的增加而增加，相對的兩者的短路電流密度(Jsc) 均在P層厚度為50 nm時，可得到最大值，P層厚度增加到70 nm 以上時，Jsc則減少。N層厚度的增加，則是在45 nm時可得到最佳的轉換效率。I層的厚度從0.5 um 增加到1 um時，隨I層厚度增加 Voc、Jsc 都明顯增加，太陽光吸收量也增加以致光電轉換效率的提升。
本研究結果顯示，薄膜的結晶性會隨著氫氣流量增加而變好，隨電極與基板間(E/S)距離增大而變差，而RF功率增加而變好之外，薄膜成長速率也會增加。本研究所製作之微晶矽太陽能電池最佳轉換效率為3.25 %、Voc=0.37 V、 Jsc=15.8 mA/cm2，FF=55.6 %。

關鍵字

電漿增強式化學氣相沉積 ； 微結晶矽薄膜 ； 太陽能電池

並列摘要

In this thesis, microcrystalline-silicon (uc-Si) thin films were deposited by using very high frequency (VHF) (27.12MHz) Plasma Enhanced Chemical Vapor Deposition (PECVD) and uc-Si solar cells were fabricated. Crystallinity of silicon films was examined by changing the hydrogen flow rate, the distance between electrode and substrate (E/S) and the RF power.
With the constant values of the E/S distance, the RF power and the B2H6 flow rate, the highest conversion efficiency of the solar cell was obtained when the p-layer silane concentration ratio [SC=H2/(SiH4+H2)] was increased from 98.5 to 99%. When SC was kept constant at 98.5% or 99%, the values of Voc and FF increased as the p-layer thickness increased. The highest value of the Jsc was obtained for both of SC at 98.5% and 99% with the p-layer thickness at 50nm. The decrease of Jsc values was remarkable when the p-layer thickness was at around 70 nm. The n-layer thickness was varied from 35 to 55 nm. The conversion efficiency of the solar cell was found to be best when the n-layer thickness was 45 nm.
When i-layer thickness was increased from 0.5 to 1 um, values of Voc and Jsc of the solar cell were increased significantly. The overall conversion efficiency increased when the light absorption of the uc-Si solar cell increased.
As shown in this study, the crystallinity of silicon films was better when the hydrogen flow rate and the RF power were increased, and, on the other hand, the E/S distance was decreased. The optimal performance of solar cell at the efficiency of 3.25%, the open circuit voltage at 0.37 V, the short current density at 15.8 mA/cm2, and the fill factor at 55.6% was achieved.

並列關鍵字

Plasma Enhanced Chemical Vapor Deposition ； microcrystalline-silicon thin films ； solar cell

參考文獻

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