臺灣博碩士論文加值系統

在本論文中，首先探討非晶矽薄膜在140℃下成長時的結構、光學及電學特性。使用氫氣稀釋比例Xg=0.66 作為非晶矽/單晶矽異質接面太陽能電池的成長參數。接著利用電壓-電流特性曲線量測 非晶矽/單晶矽 異質接面特性。為了改善 p型非晶矽/ n型單晶矽介面，選擇兩種方法來達到此目的。插入一層本質非晶矽薄膜在p型非晶矽/ n型單晶矽介面不但降低漏電流並且改善了填充因子。此外使用電漿處理的方法在單晶矽表面上也改善p型非晶矽/ n型單晶矽介面並且讓開路電壓提升至0.58伏特。最後為了提升短路電流，藉由成長一層n型重參雜非晶矽薄膜在晶圓背面來達成背表面電場（BSF）結構。太陽能電池特性為開路電壓( Voc=0.58伏特)、短路電流（Jsc=33.2 毫安培/平方厘米）、最大輸出功率（Pmax=11.45毫瓦/平方厘米）、填充因子（F.F.=0.595）、轉換效率11.45%。

In this thesis, the structure, optical and electrical properties of the hydrogenated amorphous silicon ( a-Si:H ) thin films which is fabricated under 140℃ are investigated first. The hydrogen dilution ratio Xg=0.66 is chosen for proper deposition parameter to fabricate a-Si:H/c-Si heterojunction solar cells. Then (i)a-Si/ (n)a-Si hetrojunction is studied by means of current-voltage characteristics measurement. In order to improve (p)a-Si:H/ (n)c-Si interface, two ways are chosen to achieve this goal. Insert an intrinsic a-Si:H at (p)a-Si:H/ (n)c-Si interface not only reduces the leakage current but also improves fill factor. Besides, implement plasma treatment on c-Si surface also improve a-Si:H/ c-Si interface and the open circuit voltage ( Voc ) is increased to 0.58. Finally, in order to increase short circuit current ( Jsc ), back surface field ( BSF ) structure is introduced by means of adding n+ layer at back side of silicon wafer. The solar cell performance is open circuit voltage ( Voc=0.58V ), short circuit current density ( Jsc=33.2mA/cm2 ), maximum output power ( Pmax=11.45mW/cm2 ), fill factor ( F.F.=0.595 ) and efficiency=11.45%.

Contents
Chapter 1 Introduction………..…….…………………….………..……............1
1.1SolarEnergy……………………………………………….…….......................1
1.2 Brief history of solar cells……………………………….…….........….1
1.3 HIT solar cells……………………………………………………...................2
Chapter 2 Experiments…………………………………………….…….................5
2.1 Deposition System - PECVD……………………………..................5
2.2 Substrate Preparation………………………………........……...….......6
2.3 Deposition Procedures – PECVD………………………...…...........…7
2.4 Measurement Techniques………………………….………................…12
2.4.1 Film Thickness……………………………………………....................12
2.4.2 Current – Voltage Characteristics………………..….......….12
2.4.3 Transmittance and Reflectance……………….………............13
2.4.4 Spectral Response…………………………….…………..................13
2.4.5 Introduction of FTIR ……………………….………..…..............13
Chapter 3 Properties of Hydrogenated Amorphous Silicon and HIT Solar Cells………………………………………………………………..................19
3.1 Experiments…………………………………………......................…………19
3.2 Results and Discussion……………………………..…………..............20
3.2.1 Structure Properties of a-Si:H……………..………….........…20
3.2.2 Optical Properties of a-Si:H………………….………...........…21
3.2.3 Electrical Properties of a Si:H…………………………..........22
3.3 Intrinsic (i)a-Si/ (n)c-Si Heterojunction……….………..…….29
3.4 HIT Solar Cells with no Buffer Layer………………….…….......36
3.4.1 The Fabrication of HIT Solar Cells with no Buffer Layer…………………………………………………………..............................37
3.4.2 Current-Voltage Characteristics………...…………….........38
3.4.3 The Optimization of p Layer Thickness…………...…......42
Chapter 4 HIT Solar Cells with Buffer Layer and Back Surface Field (BSF) Structure…………………………………………………….…..............47
4.1HIT Solar Cells with Buffer i layer…………………………........…47
4.1.1 The Purpose of Buffer i Layer…………….……………...........47
4.1.2 The Fabrication Processes of HIT Solar Cell with Buffer i Layer……………………………………………………………....................48
4.1.3 The I-V Characteristics of HIT Solar Cells with Buffer i Layer…………………………………………………………............................50
4.2 The Plasma Treatment on HIT Solar cells………………...…....52
4.2.1 Experiments…………………………………………….......................52
4.2.2 Results and Discussion……………………….…………...............59
4.3 HIT Solar cells with BSF Structure………………………..........67
4.3.1 The Fabrication Processes of HIT Solar Cells with BSF Structure………………………………………….………….….........................67
4.3.2 Results and Discussion…………………………………................68
Chapter 5 Conclusions………………………………………………….................75
References………………………………………………………….........................77

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