Eco-Friendly Ag2Te/Ag2S Colloidal Quantum Dots for Short-Wave Infrared Photodetector Application
- 주제(키워드) Colloidal quantum dot , Eco-friendly , Core-shell , SWIR , photodetector
- 발행기관 고려대학교 대학원
- 지도교수 Se-Woong Baek
- 발행년도 2024
- 학위수여년월 2024. 8
- 학위명 석사
- 학과 및 전공 대학원 화공생명공학과
- 원문페이지 57 p
- 실제URI http://www.dcollection.net/handler/korea/000000288774
- UCI I804:11009-000000288774
- DOI 10.23186/korea.000000288774.11009.0001568
- 본문언어 영어
초록/요약
Ag2Te colloidal quantum dots (CQDs) are attracting attention in near infrared (NIR)-shortwave IR (SWIR) optoelectronic applications because of their small bandgap, which allows for absorption and/or emission in the SWIR region, low toxicity, excellent electrical and optical properties. However, conventional synthetic routes produce low-quality Ag2Te CQDs such as poor size distribution and high polydispersity because Ag2Te with low formation energy can be easily decomposed during the synthesis process. In this study, monodisperse Ag2Te CQDs that can absorb and emit the light in the 1100~1500 nm wavelength range were synthesized via controlling the precursor ratio of Ag to Te and their reactivity within the synthetic condition to prevent Ag2Te CQD decomposition. We also synthesized core/shell type Ag2Te/Ag2S CQDs leading to improving the chemical stability as well as the photoluminescence (PL) intensity in the SWIR region by reducing the surface defects of Ag2Te CQD core. As a result, the Ag2Te/Ag2S CQD-based photodetector showed device performance with an external quantum efficiency (EQE) of 8.3 %, responsivity (R) of 0.11 A/W, and specific detectivity (D*) of 1.2×1011 at 1550 nm. This approach provides a promising pathway for developing non-toxic, high-performance NIR-SWIR photodetectors through innovative synthesis strategies and surface engineering.
more목차
TABLE OF CONTENTS
ABSTRACT i
국문 초록 ii
TABLE OF CONTENTS iv
LIST OF TABLES v
LIST OF FIGURES vi
CHAPTER 1. INTRODUCTION 1
CHAPTER 2. THEORETICAL BACKGROUND 4
2.1 Physics characteristics of CQDs 4
2.2 Lamer mechanism 5
2.3 Core/shell CQDs 6
CHAPTER 3. RESULTS AND DISCUSSION 7
3.1 Size-tunable Ag2Te CQDs 7
3.2 Surface analysis of Ag2Te CQDs 15
3.3 Passivation strategy: Ag2Te/Ag2S core/shell CQDs 25
3.4 Device performance of CQD photodiode operated at 1,550 nm 31
CHAPTER 4. CONCLUSION 39
CHAPTER 5. EXPERIMENTAL SECTION 40
5.1 Materials 40
5.2 Synthesis of Ag2Te CQDs 40
5.3 Synthesis of Ag2Te/Ag2S core/shell CQDs 41
5.4 Device fabrication 42
REFERENCES 43
