本論文中,介紹了以非晶矽為主的薄膜太陽能電池。一開始先介紹了關於非晶矽的一些材料特性,以及所有在模擬中所用到的參數。然後模擬單一吸收層的非晶矽以及微晶矽,並且將結果與實驗值做比較。除此之外,針對單一吸收層的非晶矽以及微晶矽,做了對吸收層的厚度的最佳化。 接下來探討將兩層結構串在一起,也就是串疊型的太陽電池。由於兩層結構的介面需要一層”穿隧接面”來讓光電流得以在介面複合,因此在模擬中必須將此考慮進去。然後將模擬結果跟實驗值比較也得到吻合的結果。因為串疊型的太陽電池必須考慮上下兩層結構所產生的電流要盡量吻合,才能達到比較好的輸出功率。因此做了上下兩層結構的厚度最佳化模擬。 由於材料特性的關西,太陽光之中能量比較小的部份並沒有辦法被非晶矽以及微晶矽所吸收,所以探討了加上一層鍺,並且發現可以提升太陽電池的轉換效率。因為鍺材料比較昂貴,所以也模擬了鍺的厚度對於效率的影響,希望用較少量的鍺來達到提升效率的目的。最後提出了一個新的結構:p-i-i-n。模擬之後發現,此結構的效率跟串疊兩層的太陽電池差不多。由於此結構比起串疊式較為簡單,希望可以藉此減低製程困難度。
In this thesis, the amorphous Si based thin-film solar cell is introduced. First, the model for single junction simulation is established. The disorder in the amorphous Si, which causes the tail states and deep states distribution, is also considered in the simulation. The single junctions of amorphous Si and microcrystalline Si are compared with the experiment data. Furthermore, the optimal thicknesses of i-layer of amorphous Si and microcrystalline Si are discussed. The simulation of double junction with two p-i-n single junctions in series is also discussed. For the current matching, the optimal thicknesses of top and bottom cells are discussed. With the addition of Germanium layer, the efficiency of triple junction solar cell could reach about 12%. Finally, the pi-i-n structure provides a new concept for fabricating solar cells.