Synthesis and Optical properties of ZnxCd1-xSe Alloy Nanowires
- 주제(키워드) nanowire , photosensor
- 발행기관 고려대학교 대학원
- 지도교수 남 산
- 발행년도 2009
- 학위수여년월 2009. 8
- 학위명 석사
- 학과 일반대학원 신소재공학과
- 세부전공 신소재공학전공
- 원문페이지 50 p
- 실제URI http://www.dcollection.net/handler/korea/000000009817
- 본문언어 영어
- 제출원본 000045550540
초록/요약
Nanowire photo-sensors were fabricated by growing ZnxCd1-xSe alloy nanowires bridging the gap between two pre-patterned Au catalysts and their optical properties were characterized by photo-current measurements. The bandgap energy of alloy Zn1Cd1-xSe nanowires ranges from 1.6eV (CdSe) to 2.7 eV (ZnSe), which corresponds to red to green spectral region. The fabrication procedure is simple yet efficient in that electrical contacts to alloy Zn1Cd1-xSe nanowires are self-assembled during the synthesis of nanowires, which does not require any tedious and time-consuming processes such as e-beam lithography. From scanning electron microscope (SEM), transmission electron microscope (TEM) and x-ray diffraction (XRD) studies, we found that the ZnxCd1-xSe nanowires were single crystalline without any phase separation or perfectly alloyed in a entire range of Zn composition. These sensors displayed excellent photo-sensing properties; photo-induced currents were dramatically decreased when the photon energy incident on the sample is below the bandgap energy of ZnxCd1-xSe nanowires. In on-off switching operations, we found that CdSe sensor has slower response and recovery behaviors than ZnSe and Zn0.72Cd0.28Se ones, which is attributed to the adsorption and desorption of O2 on the surface of CdSe nanowires. The present results demonstrate that semiconductor nanowires can be perfect building blocks for practically-applicable nano-devices.
more목차
1. Introduction 1
2.Background 5
2.1. Growth Mechanism of Vapor-Liquid-solid 5
2.2. ZnSe and CdSe nanowires 6
2.3. ZnxCd1-x Se alloy nanowires 8
3. Experimental 11
3.1. Synthesis of ZnxCd1-xSe nanowires 11
3.2. Fabrication of of ZnxCd1-xSe nanowires photodetector 12
4. Result and Discussion 18
4.1. Growth and Morphology analysis of ZnxCd1-xSe alloy nanowires 18
4.2. Optical Properties of ZnxCd1-xSe alloy nanowires 25
4.3. Photodetecting Properties of ZnxCd1-xSe alloy nanowires 27
5. Conclusions 36
References 37
