高等学校化学学报

高等学校化学学报 ›› 2004, Vol. 25 ›› Issue (9): 1593.

• 研究论文 • 上一篇    下一篇

反胶束法合成Cd1-xMnxS量子点及其发光性能研究

庞起1,2, 郭必成2, 王建农2, 杨世和3, 王玉琦2, 葛惟昆2, 龚孟濂1,2   

  1. 1. 中山大学化学与化学工程学院, 广州510275;
    2. 香港科技大学物理系;
    3. 香港科技大学化学系, 香港九龙清水湾
  • 收稿日期:2004-02-23 出版日期:2004-09-24 发布日期:2004-09-24
  • 基金资助:

    香港研究基金会基金(批准号:HKUST6069/02P)资助.

Synthesis of Cd1-xMnxS Quantum Dots via Reverse Micelles and Its Photoluminescence Performance

PANG Qi1,2, GUO Bi-Cheng2, WANG Jian-Nong2, YANG Shi-He3, WANG Yu-Qi2, GE Wei-Kun2, GONG Meng-Liang1,2   

  1. 1. School of Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou 510275, China;
    2. Department of Physics;
    3. Department of Chemistry, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
  • Received:2004-02-23 Online:2004-09-24 Published:2004-09-24

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摘要： 应用反胶束法制备了稀磁半导体Cd1-xMnxS量子点.量子点的大小可通过改变ωo值(wo=[水]/[表面活性剂])来控制.高分辨透射电镜的分析结果表明,量子点呈单分散性,是几乎没有缺陷的单晶体.量子点的大小约为4.8～6nm,随wo值增大而增大.电子能谱(EDS)测定结果表明,Mn2+离子在量子点中的摩尔分数为1.5%.由电子自旋共振(ESR)分析确定一部分Mn2+离子取代Cd2+离子位置而位于晶格,另一部分Mn2+离子位于Cd1-xMnxS的表面或间隙位置.吸收光谱显示,随着量子点变小,吸收带边发生蓝移,显示明显的量子尺寸效应.光致荧光光谱分析表明,发光峰属于Mn2+的4T1-6A1跃迁,而且随着ωo和粒径的增大,发光峰从2.26,2.10,2.05eV红移到1.88eV;其发光峰偏离2.12eV,主要是由于Mn2+离子位于扭曲的四面体晶体场所致.

关键词: 量子点, 稀磁半导体, Cd1-xMnxS, 反胶束, 光致荧光

Abstract: Incorporation of diluted magnetic semiconductors (DMS) in quantum confined systems opens new possibilities for the spin-dependent electronics due to the combination of the exchange interaction and the quantum confinement. In this work, we focus on the synthesis and optical properties of Cd1-xMnxS quantum dots (QDs). Cd1-xMnxS quantum dots (QDs) were prepared via a reverse micelles. The size of dots was controlled by changing the ratio of wo (wo=[H2O][AOT]). A series of Cd1-xMnxS QDs samples with wo varying from3.5 to 5.5 were prepared. A high-resolution electron transmission microscopy (HRTEM) study of QDs with wo=3.5 shows that the QDs are nearly mono-dispersed with an average diameter around 4.8 nm and the QDs are defects-free single crystals. The Cd1-xMnxS QDs size is varying from 4.8, 5.1, 5.3 to 6.0 nm with wo varying from3.5, 4.5, 5.0 to 5.5. The molar fraction of Mn2+ in the Cd1-xMnxS dots is about 1.5% with respect to (Mn2++Cd2+) determined by X-ray energy dispersion spectroscopy. Electron spin resonance spectroscopy shows that Mn2+ ions are in tetrahedral sites indicating that Mn2+ are incorporated into the CdS lattice. The absorption spectra of these samples exhibit a well-defined excitonic peak located from2.88 eV to 3.28 eV corresponding to the different values of wo. The longer wavelength of the absorption peak is exhibited with the larger wo. Most interestingly, the photoluminescence emission peaks are red-shifted from2.26 eV to 1.88 eV with increasing the wo values from3.5 to 5.5. These emission peaks are believed to originate from the Mn2+ 4T1-6A1 transitions in associated states.

Key words: Quantum dots, Diluted magnetic semiconductors, Cd1-xMnxS, Reverse micelles, Photoluminescence

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