雷射，因其高能量集中、近單色光及高度同調的特性，成為用途相當廣泛的應用元件。而將雷射的尺寸微縮至奈米等級，則能更進一步將其與積體電路整合，形成「積體光路」。
本實驗藉由金屬-氧化物-半導體（ＭOS）結構之奈米雷射以表面電漿共振方式突破繞射限制。氧化鋅奈米線作為半導體材料有著寬能隙與極大的激子束縛能，使其成為室溫下優良的增益介質；原子級平坦的鋁基板提供較低的能量損耗；高介電係數之氧化物的引入則可以大幅度降低雷射閥值。
藉由不同種類的氧化物進行結構上的更替可以發現氧化物介電係數越高，伴隨著更高強度的侷限住金屬及氧化物介面所激發的表面電漿，能有效降低雷射閥值。除此之外，因表面電漿在垂直介面上的傳遞機制，使在一定尺寸下，體積越小的共振腔能更有效的將能量傳遞給增益介質，同樣使雷射閥值降低。
綜合上述氧化物種類及厚度的不同所帶來的閥值改變，將提供奈米雷射更好的效率與更多可能。

Lasers in nanoscale have been found to be a useful device in nano-science and nano-technology. Compared with conventional lasers, it transmits signal in a faster and more efficient way. Accompanied by the improvement of nanolasers, it is promising to integrate with IC circuits. Thus, not only the delivering speed but the amount of data for digital age will rise to a higher level.
In the present study, we demonstrate Surface plasmon polariton (SPP) nanolasers consisting of ZnO nanowires coupled with single-crystalline aluminum film and high dielectric constant interlayer. High quality ZnO nanowires synthesized in a three-zone horizontal furnace acted as gain media to operate lasing at room temperature. Single-crystalline aluminum film grown with molecular beam epitaxy is critical to decrease plasmonic losses. Dielectric layers (SiO2, TiO2, Y2O3, HfO2 and ZrO2) deposited by E-beam evaporator were inserted between ZnO nanowires and Al film to lower the lasing threshold.
The thresholds for lasing were measured to be considerably low with the addition of dielectric layer. Such suppression is attributed to dielectric layer mediating strong confinement of optical field in the subwavelength regime. The threshold value for lasing was found to decrease with increasing dielectric constant for different dielectric layers. It is attributed to the reduction in the volume of resonant cavity leading to the increase in the transfer energy for lasing. The results provide crucial information for the development of efficient and practical nanolaser in nanodevices.

目錄
Contents 1
Abstract 4
摘要 5
誌謝 6
1. Introduction 7
1.1. Motivation 7
1.2. Overview of Nanotechnology 8
1.2.1. One-Dimensional Nanostructures 9
1.3. Theoretical Background of Electromagnetism 11
1.3.1. Electromagnetism in Dielectrics 11
1.3.2. Electromagnetism in Metals 14
1.3.3. Mechanism for Surface Plasmon Polaritons 15
1.3.4. Surface Plasmon Polaritons in Nanolasers 18
1.4. Metal/ Oxide/ Semiconductor Structure Nanolaser 19
1.4.1. Aluminum Substrate for Metal Layer 20
1.4.2. Promising application of Aluminum films in quantum computing 21
1.4.3. Dielectric materials 21
1.4.4. ZnO Nanowires for Semiconductor 25
2. Experimental Procedures 26
2.1. Synthesis of ZnO nanowires 27
2.1.1. Preparation of Substrate 27
2.1.2. Growth in a Horizontal Tube Furnace 28
2.2. Epitaxial Aluminum Growth by Molecular Beam Epitaxy (MBE) 29
2.3. Preparation of Dielectric layers 30
2.4. Fabrication of Nanolaser 30
2.5. Scanning Electron Microscope (SEM) Observation 30
2.6. Transmission Electron Microscope (TEM) Observation 32
2.7. Atomic Force Microscope (AFM) Observation 33
2.8. X-ray Diffractometer Measurement 34
2.9. Electron Probe MicroAnalyzer (EPMA) measurement 35
2.10. Spectroscopic Ellipsometer Measurement 36
2.11. Micro-Photoluminescence (µ-PL) Measurement 37
3. Results and Discussion 38
3.1. ZnO Nanowires 38
3.2. Epitaxial Aluminum Film 42
3.3. Dielectric Layers 43
3.3.1. Silicon Dioxide (SiO2) 44
3.3.2. Titanium Dioxide (TiO2) 45
3.3.3. Yttrium oxide (Y2O3) 46
3.3.4. Hafnium Dioxide (HfO2) 47
3.3.5. Zirconium Dioxide (ZrO2) 49
3.4. Metal/ Oxide/ Semiconductor Structured Nanolaser 50
3.5. Effects of Different Dielectric Layers on Lasing Performance 50
3.5.1. 5 nm SiO2 50
3.5.2. 5 nm TiO2 52
3.5.3. 5 nm Y2O3 53
3.5.4. 5 nm HfO2 55
3.5.5. 5 nm ZrO2 56
3.5.6. Comparison of Different Dielectric Layers on Lasing Performance 57
3.6. Effects of Dielectric Layer Thickness on Lasing Performance 59
3.6.1. 5 nm TiO2 60
3.6.2. 10 nm TiO2 60
3.6.3. 15 nm TiO2 62
3.6.4. Comparison of Different Thickness on Lasing Performance 63
3.6.5. Comparison on Lasing Performance with other Relevant Works 64
4. Summary and Conclusions 66
5. Future Prospects 67
5.1. Quantitative analysis for cavity loss 67
5.2. Surface plasmon polariton nanolasers based on graphene 68
6. References 70

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