抗反射技術可使入射光與太陽能電池元件有較佳的耦合，但現行抗反射技術在反射率、頻寬、角度相依性、尺寸、均勻度以及成本都具有或多或少的缺點。本論文提出使用鍍銀薄膜，產生金屬誘發蝕刻機制，實現在矽基材上可製作出具有低反射率，大頻寬，低角度相依性，可大面積製作且均勻度佳的矽奈米線陣列抗反射膜。並分析不同高度下其奈米線陣列之反射率，穿透率，吸收率的變化。我們發現垂直排列矽奈米線在高度為0.8 贡m時，太陽光譜加權之光吸收值即可達到0.9且無明顯之次能隙吸收現象；反之，6.98 贡m長之矽奈米線雖有較低的光反射率，但其較高之次能隙吸收值顯示此結構產生的表面復合效應相當嚴重。為了更加提昇短矽奈米線的光吸收特性，我們進一步使用氫氧化鉀蝕刻液蝕刻奈米線，得到具有尖塔形貌之折射率漸變結構，成功地降低奈米線之光反射率。
最後我們利用擴散製程實現具有奈米線薄膜之太陽能元件，其開路電壓、短路電流密度、填充因子以及轉換效率分別為0.51V，19.54mA/cm2、0.54以及5.57%。比較相同製程所做之一般型太陽能電池轉換效率為4.26%，奈米線抗反層提升1.31%的轉換效率。

Surface antireflection techniques are important for coupling incident light into solar cells. But current antireflection techniques are not all perfect at reflectivity, bandwidth, angular, independency, size, cost and uniformity。In this thesis, we propose and novel approaches to fabricate tapered silicon nanowire array using simple wet chemical etching process. This method enables large wafer-scale fabrication with low cost and improved uniformity.
We investigate that reflectance, transmittance, and absorption rate for different heights of silicon nanowire arrays. We found that when vertically-aligned silicon nanowires is of 0.8μm high, the spectrum of solar weighted absorption can reach to 0.9 without absorptions of visible sub-energy gap phenomenon. On the contrary, the 6.98μm long SiNW has low optical reflectivity, but its higher sub-bandgap absorption values show the effect of more surface defects.
In order to upgrade the light absorption character of short nanowires array, we apply a post chemical etching process with a diluted KOH to achieve index of gradual refraction architecture. The result is that we successfully lower the light index of refraction of SiNWs.

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