開發低反射矽奈米表面結構製作技術並應用於多晶矽太陽能電池

Development of antireflective silicon nanostructures for polycrystalline silicon solar cells

林柏穎(Po-Ying Lin)

指導教授 ： 陳一塵

國立中央大學/工學院/材料科學與工程研究所/碩士(2015年)

摘要

多晶矽太陽能電池因為在成本與效能間的優異平衡下成為目前光伏產業中的主流產品。為了提升轉換效率，除了考量半導體材料本身的物理特性或材料內部缺陷等因素外，如何能夠最有效的利用電池所接收到的入射太陽光成為提升太陽能電池效能的重要課題。傳統上是以鹼金屬溶液對單晶矽太陽能電池進行表面粗糙化處理。但此蝕刻液會在多晶矽的晶界處發生裂縫與不理想的階梯狀結構使其抗反射效果不佳。此外由於晶面的選擇性蝕刻而產生外觀上的顏色不均勻則在商業應用上有美觀的疑慮。
因此本研究結合 HNO3/HF 濕蝕刻和 SF6/O2 反應式離子蝕刻 (RIE) 對多晶矽太陽能電池表面製備微米-奈米尺寸的抗反射結構。並藉由調整製成參數如：壓力、混和氣體比例和射頻功率以獲得具備外觀色澤均勻同時保有低反射率的最佳化蝕刻結構。相較於只以酸蝕刻進行粗糙化處理的標準試片，具有最佳化 RIE 織構的多晶矽太陽能電池其照光下的短路電流增加 2.04 (mA/cm2)。且由於光捕捉 (light trapping) 效應的貢獻使光電轉換效率提升 2.58%。

關鍵字

多晶矽太陽能電池 ； 粗糙化處理 ； 濕蝕刻 ； 反應式離子蝕刻

並列摘要

Multi-crystalline silicon (mc-Si) solar cells dominate PV manufacturing due to its excellent balance between cost and efficiency. The performance of mc-Si solar cells depends critically on the optical losses caused by the high reflectivity of c-Si wafers. In addition, the color difference on the grains with various crystalline orientations after alkali texturing causes aesthetic concerns in residential applications. At the first stage of this study, in order to obtain the optimized dimension of the structure, the simulation of surface textured was implemented by RCWA method. The textured mc-Si with micro-sized and nano-sized structures were fabricated using reactive ion etching (RIE) combined with wet chemical etching. A surface modification of mc-Si with low reflectivity and uniform color can be achieved by adjusting the etching parameters (e.g., pressure, gas mixture and RF power). Compared with the reference wet etching texture, mc-Si solar cell with optimized RIE textured was improved 2.04 (mA/cm2) in short current density. Conversion efficiency was enhanced 2.58%, since the contribution of excellent light trapping effect.

並列關鍵字

texture ； multi-crystalline silicon ； wet etching ； reactive ion etching

參考文獻

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