학술논문
Enhanced photoluminescence of Co2+ ions in ZnCoO/ZnMgO multiple quantum wells and the fluorescence energy transfer mechanism.
Document Type
Article
Author
Source
Subject
*PHOTOLUMINESCENCE
*QUANTUM wells
*COBALT
*ZINC compounds
*ENERGY transfer
*PULSED laser deposition
*SAPPHIRES
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Language
ISSN
0022-2313
Abstract
Using a pulsed laser deposition system, ZnCoO/ZnMgO multiple quantum well (MQW) samples were grown on c -plane sapphire substrate with a ~20 nm thick ZnO buffer layer. Compared with monolayer ZnCoO film, the MQW samples exhibited obviously enhanced Co 2+ photoluminescence (PL) at ~1.80 eV and multiple-phonon resonant Raman scattering (RRS). The enhancement in multiple-phonon RRS was due to the introduction of ZnMgO barrier layer. The enhanced Co 2+ PL was assigned to the quantum confinement effect (QCE) of MQW samples. However, QCE was found not helpful to prevent the band-gap PL quenching. Co 2+ 3d electronic states were proved to be highly localized and a mechanism of fluorescence resonance energy transfer (FRET) between ZnO excitons and the localized Co 2+ 3d states was proposed. [ABSTRACT FROM AUTHOR]