臺灣博碩士論文加值系統

在非晶矽/單晶矽異質接面的太陽能電池中，元件特性與異質接面的品質和抗反射結構是強烈相關的。首先，本論文藉由提高非晶矽之成長溫度來改善薄膜的特性進而提升介面的品質，其中，利用高溫成長之本質非晶矽層作為保護層，元件的開路電壓因此獲得明顯的提升;同時，也使用一種介面處理方法來改善介面的品質，在本論文該方法稱之為電漿處理，是使用電漿增強化學氣相沉積方法在實際成長非晶矽薄膜之前，先以氫氣之低能量電漿對單晶矽基板表面作預處理。由於介面的良好鈍化和內建電位的增加，使用氫氣電漿處理方法可以有效提升元件之開路電壓和填充因子，進而增加太陽能電池的轉換效率。接著，本論文使用抗反射結構來改善元件特性。利用化學濕蝕刻方法製造的微結構基板，可顯著減少基板的反射率，利用此有效的抗反射結構，元件之光電流可以有顯著的提升，進而提升轉換效率。最後，將電漿處理及背表面電場應用在此結構上，元件效率可達16.38 %。

In a-Si:H/c-Si heterojunction solar cells, the key factor to the high performance are the a-Si:H/c-Si heterointerface and anti-reflection structure. First, we use the high temperature (250 ℃) to deposit a-Si:H layers to improve the interface passivation due to the films quality is better. By inserting high temperature deposition of intrinsic a-Si:H to be the passivation layer, the open circuit voltage (Voc) is apparently increased. Moreover, we concentrate on the interface treatment of the a-Si:H/c-Si interface. Before depositing the a-Si:H films by PECVD, we use the hydrogen treatment to pre-treat the c-Si surface by a low energy plasma. The hydrogen plasma treatment improve both the open circuit voltage (Voc) and fill factor (F.F.) and thereby increase the conversion efficiency of solar cell due to the good passivation of interface and the increase of build-in potential. Second, the anti-reflection structure is introduced to improve the device performance. We use textured substrate formed by wet chemical etching method. By means of this structure, the short circuit current density (Jsc) can be largely enhanced and the efficiency is improved. Finally, the plasma treatment and BSF structure are used in this textured substrate of HIT solar cell. The conversion efficiency is achieved to 16.38%.

Chapter 1 Introduction…………………………………………………1
1.1 Solar Energy…………………………………………………………...1
1.2 Brief History of Photovoltaic Devices……………………....1
1.3 HIT Solar Cells…………………………………………………….....3
1.4 Motivation of the Research……………………………………...4
1.5 Outlines of the Thesis……………………………………………....7
Chapter 2 Experiments…………………………………………………8
2.1 Fabrication equipments…………………………………………..8
2.1.1 Deposition System PECVD………………………………….............8
2.1.2 Sputter and Resistive thermal evaporation……………………......13
2.2 Substrate Preparation……………………………………............14
2.3 Deposition Procedures – PECVD……………………............14
2.4 Measurement Techniques……………………………………….16
2.4.1 Film Thickness………………………………………………………16
2.4.2 Surface characterization…………………………………………….17
2.4.3 Transmittance and Reflectance……………………………………..17
2.4.4 Current – Voltage Characteristics………………………………….19
2.4.5 Spectral Response……………………………………………...........19
2.4.6 Introduction of FTIR………………………………………………..21

Chapter 3 Properties of Hydrogenated Amorphous Silicon and HIT Solar Cells with Flat structure ………..24
3.1 Experiments………………………………………………………….24
3.2 Results and Discussion…………………………………………..27
3.2.1 Structure Properties of a-Si:H……………………………………..27
3.2.2 Optical Properties of a-Si:H ………………………………………..30
3.2.3 Electrical Properties of a Si:H……………………………………...31
3.2.4 HIT Solar Cells without Buffer layer……………………………...35
3.2.4.1 The Fabrication of HIT Solar Cells without Buffer intrinsic Layer…………………………………………………………………..35
3.2.4.2 Current-Voltage Characteristics……………………………….37
3.2.5 HIT Solar Cells with Buffer i Layer……………………………….47
3.2.5.1 The Fabrication Processes of HIT Solar Cells with Buffer i Layer…………………………………………………………………..48
3.2.5.2 The I-V Characteristics of HIT Solar Cells with Buffer i Layer…………………………………………………………………..49
3.2.6 HIT Solar cells with BSF Structure ………………………………..55
3.2.6.1 The Fabrication Processes of HIT Solar cells with BSF Structure ………………………………………………………………55
3.2.6.2 The characteristics of HIT Solar Cells with BSF Structure….............................................................................................56

Chapter 4 The effect of plasma treatment and anti-reflection coating on the performance of HIT Solar Cells……………………………………………………………………………….62
4.1 The Effect of Plasma Treatment on HIT Solar cells...63
4.1.1 Experiments…………………………………………………………63
4.1.2 Results and Discussion……………………………………………...64
4.2 HIT Solar Cells on Textured Substrate…………………..70
4.2.1 The Fundamentals of Anti-reflection coating..................................70
4.2.2 Fabrication of Texture Substrate ………………………………..70
4.2.3 Surface morphologies of Textured Substrate……………………...70
4.2.4 Optical Properties of Textured Substrate………………………….73
4.2.5 HIT Solar Cells on Textured Structure……………………………74
4.2.5.1 The Fabrication Processes of HIT Solar cells with no Buffer I Layer on Textured structure……………………………………………74
4.2.5.2 The I-V Characteristics of HIT Solar Cells with no Buffer I Layer on Textured structure…………………………………………………...75
4.2.5.3 The Fabrication Processes of HIT Solar cells with Buffer I Layer on Textured structure…………………………………………………...83
4.2.5.4 The I-V Characteristics of HIT Solar Cells with Buffer I Layer on Textured structure………………………………………………………84
4.3 The Plasma Treatment on textured HIT Solar cells with Buffer I Layer…………………………………………………....89
4.3.1 Experiments…………………………………………………………89
4.3.2 Results and Discussion……………………………………………...90
4.4 The Improvement of textured HIT Solar cells by using BSF Structure…………………………………………………..94
4.4.1 The Fabrication Processes of textured HIT Solar cells with BSF Structure…………………………………………………………………...94
4.4.2 The Characteristics of textured HIT Solar cells with BSF Structure…………………………………………………………………...95

Chapter 5 Conclusions………………………………………………..101

References……………………………………………………………………103

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