Studies of magneto-optical properties of CdTe/CdSe/ZnS multilayer nanoparticles
| Autor: | Chia-Ching Huang, 黃家慶 |
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| Rok vydání: | 2008 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 96 Although the absolute phase of a quantum state is not measurable, the relative phase of a coherent charged particle wave could be manipulated. In the famous Aharonov-Bohm effect for an electron traveling in a ring, interference pattern was observed with changing magnetic flux. Recently, optical Aharonov-Bohm has received much attention. The effect of the relative phase of the electron and hole in a magnetic field on the excitonic properties in semiconductors was studied theoretically and oscillation of the excionic energy and quenching (or oscillation) of the integrated photoluminescence intensity with magnetic field were predicted. Experimentally, evidence of the optical Aharonov-Bohm effect was observed with negatively charged exciton in InGaAs/GaAs quantum ring and polarized exciton in type-II GaAs-GaSb system. In this thesis we’ll present our studies on the optical Aharonov-Bohm in CdTe/CdSe/ZnS system. The nanoparticles were grown by chemical method and have size of about 6 nm and the band alignment between the core (CdTe) and the shell (CdSe) is a type–II band alignment. The addition of ZnS layer is to passivate the surface of CdSe and to enhance the light emitting efficiency. Magneto-photoluminescence experiment was performed at T=1.4 K with a 14 T superconducting magnet in conjunction with a green diode laser and a monochromator. Oscillation on the peak energy of the photoluminescence spectra as well as oscillation in the integrated intensity as a function of magnetic field were observed and are attributed to the optical Aharonov-Bohm-like effect. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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