二硒化銅銦薄膜在元素態硫蒸氣氣氛下退火處理後可以完全轉換成二硫化銅銦。本論文利用分子束磊晶系統，將二硒化銅銦薄膜試片曝露於加熱的硫源瓶，以完成硫化轉換製程。實驗結果顯示，1微米厚的二硒化銅銦薄膜在硫分子束通量4.5×1016 原子/公分2-秒，且於基板溫度450℃退火處理5分鐘條件下，可完全轉換成二硫化銅銦。在此退火溫度下，比較其他的文獻報告之完全硫化轉換所需時間，本結果是最短的一個。影響硫化轉換速度的因素包括硫蒸氣通量、薄膜結晶性以及原始薄膜化學組成，其中又以原始薄膜化學組成最為重要。富銅含量之二硒化銅銦薄膜中會伴隨有二次相硒化亞銅出現，此二次相會加速硫化轉換製程之速度，富銅含量之二硒化銅銦薄膜試片經由氰化鉀溶液蝕刻移除二次相硒化亞銅後，可發現其硫化轉換速度明顯減緩。本研究也提出二次相硒化亞銅在硫化轉換製程機制所扮演之角色。

Thin films of CuInSe2 can be completely converted into CuInS2 after annealing in elemental sulfur vapor. In this thesis, the sulfide conversion process was done in an MBE chamber and the film was exposed to a heated sulfur source. Our experiments showed that complete conversion of a 1.0 μm-thick CuInSe2 film into CuInS2 was achieved when the film was annealed in a sulfur beam flux of 4.5x1016 atoms/cm2-sec at 450℃ for 5 minutes. This is the shortest conversion time ever reported for the same annealing temperature. The speed of conversion process depended on sulfur vapor flux, film crystallinity, and original film composition. Among them, the film composition was the most important factor. The presence of Cu2Se phase in Cu-rich CuInSe2 film enhances the sulfide conversion process and confirmed by KCN etching of a Cu-rich sample. The role of Cu2Se phase in sulfide conversion was investigated. The sulfide conversion mechanism also presented in this work.

TABLE OF CONTENTS
ABSTRATE
LIST OF FIGURE………………………………………………VII
LIST OF TABLE…………………………………………….XI

CHAPTER 1 INTRODUCTION 1
1.1 Device Physics－How does a Solar Cell Work 1
1.2 The Structure of Thin Film Solar Cell 4
1.2.1 Substrate Solar Cell－CIGS Solar Cell 5
1.2.2 Superstrate Solar Cell－CdTe and a-Si Solar Cell 11
1.3 Recent Progress in Photovoltaics 12
1.4 A Brief Review of CuInSe2 Deposition Processes 14
1.5 Motivation for sulfurization of CIS-based films 17
1.5.1 Decreased losses by sulfur grading 18
1.6 Purposes of this thesis 20
CHAPTER 2 GROWTH AND CHARACTERISTICS 37
2.1 Molecular Beam Epitaxy Growth System 37
2.2 Substrate cleaning 39
2.3 Thin Film Growth 42
2.3.1 CuInSe2 film 42
2.3.2 Sulfide conversion process 43
2.4 Characterization methods of thin films 44
CHAPTER 3 RESULTS AND DISCUSSION 65
3.1 The growth of CuInSe2 films 65
3.2 The effect of second phases 66
3.3 Sulfide Conversion Process 67
Chapter 4 SULFIDE CONVERSION MODELING 92
4.1 Proposed conversion model 92
4.2 Modified conversion model 93
Chapter 5 CONCLUSION 104

Chapter1
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