非晶矽/非晶矽矽基堆疊型太陽能電池

Abstract

此論文用AMPS-1D此模擬軟體模擬疊層太陽能電池，並利用高密度電漿化學沉積系統(HDPCVD)去沉積a-Si/a-Si雙結太陽能電池，經由實驗結果與模擬結果之比較，其趨勢變化大致相同，故可藉由此模擬軟體預測雙結太陽能電池之趨勢變化，大幅縮短實驗試驗時間｡ 在模擬中，在上層電池與下層電池間加入TRJ層，使得疊層電池的開路電壓可成功地疊加。並探討a-Si/a-Si雙結太陽能電池之四種不同材料組合之復合接面對於電池的影響，包含n1-a-Si/p2-a-Si、n1-a-Si/p2-μc-Si、n1-μc-Si/p2-μc-Si和n1-μc-Si/p2-a-SiC，經由比較結果得到n1-μc-Si/p2-μc-Si為最佳復合接面材料組合，乃因其在能帶圖中載子在復合接面位置較靠近，同時亦有較低的阻抗，因此載子較易復合和傳輸｡最後對a-Si/a-Si雙結太陽能電池進行優化，當上下層電池本質層分別為75nm與450nm時，可達最佳效率10.384%｡ 在實驗中，使用薄膜測厚儀分析非晶矽薄膜，得到其光能隙約在1.8eV，證實其為非晶矽薄膜｡亦使用拉曼光譜及X射線繞射衍射儀來分析微晶矽薄膜，由這些薄膜製作電池｡針對a-Si/a-Si雙結太陽能電池之復合接面參數去做變化，包括n1-a-Si/p2-a-Si及n1-μc-Si/p2-μc-Si兩種復合接面｡在n1-a-Si/p2-a-Si此復合接面中，減少其厚度可有效降低其阻值，降低n1-a-Si之摻雜氣體濃度，可減低其能障高度，進而提升載子傳輸｡當增加p2-a-Si或n1-a-Si摻雜氣體濃度時，其阻值並沒有太大變化，但可提升電池內之內建電場，提高效率｡針對上下層電池之厚度與能隙進行調變，並將p1層窗口層改為p1-a-SiC，則當上下層電池本質層厚度分別為75nm和550nm時，其效率可高達約8.5%｡而在n1-μc-Si/p2-μc-Si此復合接面中，藉由提高n1-μc-Si或p2-μc-Si摻雜氣體濃度，雖其阻值並沒有太大變化，但可提升其內建電場，亦可有效地提升電池之效率｡ 最後，亦利用AMPS-1D模擬不同能隙之下層電池，即a-Si/μc-Si雙結太陽能電池與a-Si/a-SiGe雙結太陽能電池，並對此進行優化，供以後做實驗為參考，其優化後的效率分別可高達11.198%及11.777%｡

In this article, we used AMPS-1D software to simulate tandem solar cells, and also used high-density plasma chemical vapor deposition (HDPCVD) to deposit a-Si/a-Si tandem solar cells. Comparing the experiment results with the simulation results, they almost have the same trend. Thus, AMPS-1D could be used to predict the experiment results, and reduce the time to try and error. In the simulation, we successfully added tunneling recombination junction (TRJ) to simulate tandem solar cells. This article discussed the influence of four kinds of different material compositions in the a-Si/a-Si tandem solar cells, including n-a-Si/p-a-Si, n-a-Si/p-μc-Si, n-μc-Si/p-μc-Si and n-μc-Si/p-a-SiC. The results showed that n-μc-Si/p-μc-Si is the best choice for the recombination junction (RJ) of a-Si/a-Si tandem solar cells because its low resistance and low mobility gap. Also, we optimized a-Si/a-Si tandem solar cells. When i-layer thickness of top cell and bottom cell were 75nm and 450nm individually, the efficiency could reach 10.384%. In the experiment, we used N&K analyzer to analysis a-Si film, and found that the optical gap was around 1.8eV. Also, Raman spectroscopy and X-ray diffraction were used to analyze μc-Si film. After that, these films deposited a-Si/a-Si tandem solar cells. By changing the parameters of the RJ, we found that decreasing the np junction thickness could reduce the resistance, and varying the np junction doping concentration almost didn’t change the resistance. When increasing the np junction doping concentration, the electric field could enhance and the efficiency could reach higher. With varying the i-layer thickness and the mobility gap of top cell and bottom cell and using p1-a-SiC window layer, the efficiency of a-Si/a-Si tandem solar cell could reach about 8.5%. Finally, we also used AMPS-1D to optimize a-Si/μc-Si tandem solar cells and a-Si/a-SiGe tandem solar cells to predict the experiment trend. By changing i-layer thickness and the mobility gap of top cell and bottom cell, their efficiency could reach 11.198% and 11.777% individually.