表面增強拉曼散射（surface enhanced Raman spectroscopy, SERS）是一種利用電漿效應及化學效應增強拉曼散射的技術。此種散射增強技術，可以讓我們藉由分子震盪所產生的特定光譜，了解分子的結構，而且具備許多優點，例如高靈敏度、高辨識度、高通量等。在本研究中，我們利用鋁奈米顆粒及氮化物 SERS 基板，評估去氧核醣核酸deoxyribonucleic acid, DNA)的感測效果。
氮化物 SERS 基板含有 InGaN 量子井，在雷射光的激發下，此量子井可提供大量的電荷至 SERS活性區，因而放大拉曼訊號。使用 Al 奈米顆粒的目的，是要搭配 488 nm 的光源，產生局部表面電漿共振的效應，藉此增強 DNA 的 SERS 訊號。我們發現，利用這種新式的 SERS 基板，可在
免標記的條件下，感測到 10-6 M 的單股胞嘧啶（cytosine）DNA。此外，此量子井 SERS 基板，也能分辨腫瘤 DNA 雜交後產生的特定拉曼訊號。

Surface-enhanced Raman scattering (SERS) is a light-intensifying technique that combines plasmonic enhancement and chemical enhancement, significantly boosting Raman signals. This technique delivers structural information produced by particular molecular vibrations, and has many advantages, such as high sensitivity, high selectivity and rapid-detection, etc. In this study, a nitride SERS substrate decorated by Al nanoparticles was fabricated for the detection of deoxyribonucleic acid (DNA). The substrate was built with InGaN quantum wells (QWs), from which abundant electronic charges, under laser excitation, were transferred to the SERS-active regions and thereby amplified SERS signals. The Al nanoparticles were adopted to induce localized surface plasmon resonance at the excitation wavelength of 488 nm. It was found that the label-free Al-decorated QW SERS substrate can achieve the detection limit of 10-6 M for 19-mer cytosine single-stranded DNA. The nitride substrate was also able to differentiate the hybridization event of circulating tumor DNA.

CHINESE ABSTRACT I
ENGLISH ABSTRACT II
ACKNOWLEDGMENT III
TABLE OF CONTENTS IV
LIST OF FIGURES V
LIST OF TABLES VI
LIST OF ABBREVIATIONS VII
Chapter 1 1
INTRODUCTION 1
1.1. Motivation and overview 1
1.2. Surface enhanced Raman scattering (SERS) 2
1.2.1. Theory of Surface enhanced Raman scattering (SERS) 2
1.2.2. Application of SERS 8
1.3. Deoxyribonucleic Acid (DNA) structure 8
1.4. SERS substrate for DNA detection 10
1.4.1. SERS substrate for DNA detection 10
1.4.2. DNA hybridization 12
1.5. Thesis overview: Introduction of each chapter 14
Chapter 2 15
EXPERIMENT 15
2.1. The fabrication of SERS substrate 15
2.2. Sample preparation 15
2.2.1. Cleaning process 15
2.2.2. Metal deposition process 16
2.2.3. Annealing process 16
2.2.4. DNA immobilization and hybridization on the Alumina substrates 17
2.3. SERS measurement 18
Chapter 3 19
RESULTS AND DISCUSSIONS 19
3.1. The selection of optimizing condition 19
3.1.1. Excitation laser wavelength 19
3.1.2. Metal types 22
3.2. Optimizing the fabrication of SERS substrate 25
3.2.1. Metal thickness 25
3.2.2. Annealing Temperature 28
3.3. Detection limits 31
3.4. DNA hybridization 33
Chapter 4 36
CONCLUSIONS AND FUTURE WORKS 36
4.1. Conclusions 36
4.2. Future works 36
REFERENCES 37