在本篇研究論文中，我們在基板上以濺鍍方式沉積氧化鋅成核層，再以水溶液沉積法生長氧化鋅奈米針，並對其做了相關的物性、光性、化性等特性分析。在不同基板上濺鍍氧化鋅成核層，探討晶格不匹配影響氧化鋅成核層的結晶型態，再間接影響氧化鋅奈米針的生長，晶格常數越接近氧化鋅的基板可提升氧化鋅成核層結晶化的強度。氧化鋅奈米針在光致螢光 (PL)的分析可以得知，氧化鋅奈米結構的紫外光激發峰值的位置約位於375 nm，在綠-黃色光 (550~650 nm)有小峰值的出現，文獻指出為氧化鋅內部缺陷，經由實驗得知笑氣回火處理可以填補氧化鋅內部缺陷而降低峰值。並在水溶液生長氧化鋅奈米針時照射紫外光參與反應，利用紫外光激發氧化鋅成核層產生電子電洞對，其中電洞會幫助水溶液中的氨水分解，而加快氧化鋅奈米針生長速度。氧化鋅奈米針可利用其粗化表面和光學影響的特性，在應用上可當作抗反射層。本實驗中將利用氧化鋅奈米針應用於多晶矽太陽電池上，利用氧化鋅奈米針當抗反射層以增加光穿透率，提升太陽能電池之效率。
我們利用掃描式電子顯微鏡探討表面形態，X射線光電子能譜儀探討元素比例與表面特性，微螢光光譜量測探討吸收光譜，電流-電壓曲線量測探討太陽電池特性與光電轉換效率。 實驗結果顯示，短路電流從未處理的40.49 mA提升至44.01 mA，轉換效率從未處理的13.388%，經處理提升至 14.4%。

關鍵字: 水溶液沉積法, 氧化鋅, 奈米針, 蛾眼效應, 抗反射層, 太陽電池

In this study, zinc oxide (ZnO) nanotip array will be grown on ZnO nucleation layer by aqueous solution deposition (ASD). Characteristic of the ZnO nanotip array will be investigated. We will discuss the lattice mismatch that affect the crystallization of ZnO nucleation layer and morphology of ZnO nanotip array. The PL analysis of ZnO nanotip array shows the typical emissions of narrow exciton related UV band peak at 375 nm and broad defect related green–yellow (550~650 nm) bands. The green-yellow emission (550~650 nm) is likely due to O vacancies and the emission is improved after N2O annealing at 300 oC. Under UV light illumination, the electron-hole pairs are generated in ZnO by the photoexcitation and then the pairs diffuse to the surface. Holes could enhance the decomposition of ammonia and hence the concentration of OH- will be increased. The growth rate of ZnO nanotip array could be enhanced because of the ultraviolet light illumination. ZnO nanotip array with rough surface decreases reflection, so we use ZnO nanotip array as an anti-reflection layer. After coating ZnO nanotip array on solar cell, the efficiency of solar cell is enhanced.
The morphology is observed by field emission scanning electron microscope (FE-SEM). The physical properties are characterized by X-ray diffraction (XRD). The optical properties are measured by Micro-photoluminescence (Micro-PL). The performance of the cells is measured by a semiconductor device analyzer. In our results, we grow the high performance of ZnO nanotip array on solar cell to increase the efficiency. The short-circuit current is increased from 40.49 to 44.01 mA, and the efficiency is increased from 13.388 to 14.4%.

Keywords: aqueous solution deposition (ASD), zinc oxide (ZnO), nanotip, moth eye principle, anti-reflection, solar cell

論文審定書 I
ACKNOWLEDGEMENT II
中文摘要 III
ABSTRACT IV
CONTENTS VI
LIST of FIGURES IX
LIST of TABLES XII
Chapter 1 1
Introduction 1
1.1 Properties of ZnO 1
1.2 Anti-reflective layer 2
1.2.1 Anti-reflective layer of ZnO nanotip array 2
1.2.2 Anti-reflection coating – “Moth eye” principle 3
1.2.3 Structure conditions for moth eye effect 4
1.2.4 Effective medium theories 5
1.2.5 Effective refractive index 6
1.3 Syntheses of ZnO nanotip array 10
1.4 Advantages of aqueous solution deposition (ASD) 11
1.5 Motivation 12
Chapter 2 18
Experiments 18
2.1 Substrate cleaning procedures 18
2.2 RF nucleation layer prepared by RF sputtering 20
2.2.1 Sputtering mechanism 20
2.2.2 RF sputtering for ZnO nucleation 21
2.3 ASD of ZnO nanotip array 23
2.3.1 Deposition process 23
2.3.2 Upside down process 23
2.4 Growth process of ASD-ZnO nanotip array 24
2.5 Basic mechanism of ZnO nanotip array 25
2.6 Characterization 26
2.6.1 Physical properties 26
2.6.2 Optical properties 28
2.6.3 Chemical properties 30
2.6.4 Current-voltage (I-V) Measurement 30
Chapter 3 36
Results and Discussion 36
3.1 Morphology of ASD-ZnO nanotip array 36
3.1.1 Conditions for the formation of wurtzite ZnO nanotip 36
3.1.2 Film-like layer 38
3.1.3 Crystallization of sputtering ZnO 39
3.2 Characterization of ASD-ZnO nanotip array 42
3.2.1 XRD spectra of ASD-ZnO nanotip array 42
3.2.2 Micro PL spectra of ASD-ZnO nanotip array 42
3.2.3 ESCA spectrum of ZnO nanotip array 43
3.3 Growth rate enhancement of ASD-ZnO nanotip array by UV illumination 44
3.3.1Characterization of ASD-ZnO nanotip array by UV illumination 44
3.3.2 Mechanism of ASD-ZnO nanotip array by UV illumination 47
3.4 Characterization of ASD-ZnO nanotip array on poly-Si solar cell 48
3.4.1 ZnO Sputtering affects poly-Si solar cell 49
3.4.2 The effect of Preheating ASD-ZnO nanotip array 50
3.4.3 Performance of solar cell with ZnO nanotip array 51
Chapter 4 79
Conclusions 79
References 80

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