Fabrication and Characterization of CdSe Quantum Dots

• Main Authors: CHANG HSUN TUNG, 張旭東
• Other Authors: Yang Fang Chen
• Format: Others
• Language: zh-TW
• Published: 1999
• Online Access: http://ndltd.ncl.edu.tw/handle/84339794870991752098

碩士 === 國立臺灣大學 === 物理學研究所 === 87 === In this thesis, a new method for quantum dots fabrication was proposed and successfully demonstrated. Rather than Stranski-Krastanov mode, quantum dots can also be grown under Volmer-Weber(VW) mode. Strong carrier confinement was observed in the PL spectra of CdSe/ZnS quantum dots fabricated by our proposed VW mode. The emission persists up to room temperature. It is an indication of strong excitonic effect in the quantum dot structures. In the temperature dependence of PL measurement, exciton binding energy was found to increase with decreasing size. It is found that the increase of the binding energy can be four times of the bulk value. And, the exciton binding energy is the most important factor to determine the quenching behavior of the PL spectra. Besides, we have also analyzed the behavior of the temperature dependence of FWHM, which shows that in addition to electron-phonon interaction , there exists inter-dot coupling in CdSe/ZnS quantum dots. Finally, We have compared the properties of CdSe and ZnSe quantum dots grown by our method and found that the exciton binding energy does play a key role in the optical properties of quantum dot systems.