利用AMPS-1D分析及優化矽基薄膜太陽能電池

Abstract

矽基薄膜太陽能電池的結構比起矽晶圓太陽能電池要來的複雜，因此在製程上非常的耗時，如果要優化它們會是一個龐大的工程。我們利用AMPS-1D模擬軟體來建立矽基薄膜太陽能電池模型，分析與優化它們並試圖與製程結合在一起，藉由此種方式可以有效的優先找出改良元件效率的因素或者是避免在製程上不需要的測試，已減少實際實驗所需的時間。 本篇論文的第一部分是在介紹AMPS-1D模擬軟體如何運作及參數的認識和模型的建立，以及透過不同量測方式來建立模型的完整性。在第二部份的分析及討論會先分別利用建立的模型去計算非晶矽、非晶矽鍺、微晶矽薄膜和雙接面太陽能電池的轉換效率，接著在模型上變動一些製程上可以去改變的元件參數如摻雜濃度、厚度、能隙等等，去看其對轉換效率的影響如何，並去解釋這些影響效率的因素，從這些數值計算和討論結果可以找到優化方法。 在非晶矽上，我們發現P型層和I型層以及TCO功函數對效率的改善有很大幫助；而非晶矽合金在適當調變能隙下或是利用緩衝層有助於元件優化；微晶矽部份，我們分成薄膜和元件結構討論，找出薄膜最適合的摻雜和微晶矽的優化結果，當我們優化完單一接面的的矽基薄膜太陽能電池後，我們利用這些優化完畢的子電池模型來堆疊製作高效率雙接面的矽基薄膜太陽能電池，分別是非微晶堆疊和非晶矽堆疊非晶矽鍺的薄膜太陽能電池，我們的高效率雙接面太陽能電池模型效率在非微晶堆疊可達9.34%；在非晶矽堆疊非晶矽鍺則具有10.15%的效率。

Since the structures of silicon-based thin film solar cells are more complex than Monocrystalline-silicon solar cells, it is time-consuming in processing. For this reason, to optimize Si-based thin film solar cells in processing is a lot of work. In order to solve this problem, we are use the AMPS-1D simulation program to set up models of Si-based thin film solar cells and combine with the process, moreover, we are analysis and optimize these models in simulation results. It will save us much time on experiments. In the first session of my thesis, the mathematical modeling and solution techniques of AMPS-1D had been introduced. Each parameter for setting up model was mentioned and I will list and introduce all of parameters to different material thin film solar cells’ models. In addition, measuring methods used to set up more complete models were also introduced. In the next session, first theoretically optimize the amorphous (a-Si:H) and the microcrystalline (μc-Si:H) devices characteristics, and then perform studies for micromorph and a-Si:H/a-SiGe:H tandem solar cells. In optimization, we modify various fabrication parameters with numerical calculation for each sub cell models and explain how they affect efficiency. For a-Si:H, AMPS-1D show that the TCO work function has a strongly influence on the open-circuit voltage. Moreover, the power conversion efficiency is optimized for the absorber’s layer thickness and mobility gap, also for the p-layer’s doping concentration. Finally, we are present a-Si alloyed model that has better efficiency, too. The studies next indicate a critical doping concentration of μc-Si:H films which limited the barrier height of a grain boundary (GB). Furthermore show the calculation results in different crystalline volume fraction (XC) and fabrication parameters such like absorber’s layer thickness and quality. These are enough to improve μc-Si:H solar cell efficiency . After optimizing sub cell each other, we combine the individual junctions and construct high efficiency tandem solar cells. Our models are present high efficiency 9.34% in a micromorph cell, and high efficiency of 10.15% in a-Si/a-SiGe tandem cell.