Morphology, Self-Assembly, and Heterojunction of One-Dimensional II-VI Semiconducting Nanocrystals

• Main Authors: Chia-Cheng Kang, 康佳正
• Other Authors: Pi-Tai Chou
• Format: Others
• Language: en_US
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/89623828101825638052

博士 === 國立臺灣大學 === 化學研究所 === 97 === Besides zero dimensional semiconducting nanoparticles (also referred to as “quantum dots”), one dimensional semiconducting nanocrystals with dimensions in the range of nanometer and with different aspect ratios have also drawn much attention due to their fascinating size- and shape-dependent optical and electronic properties. In this study, by using a solution-based method, CdS self-bundled arrays with an area of as large as 2.0 μm2 could be produced in the absence of an external direction-controlling process. Matching in nanorod concentration, intrinsic properties of CdS, and the hydrocarbon chains of the surfactants between adjacent CdS rods play key roles in the self-assembly. Also, the self-bundled CdS nanorods exhibit optical emission nearly free from the defect-states. In addition, by optimizing the use of surfactants and temperature, the aspect ratio of CdS nanowires with diameter of 3.5 nm can be tuned up to 300. Finally, by applying metallic nanoparticles as a protecting group, nanorods with axial heterojunctions could be obtained with a mechanism different from that of the SLS model. Results of this study could serve as basic concepts in nanocrystal architecture.