Manipulation of Carrier鈥揗n2+ Exchange Interaction in CdTe/CdSe Colloidal Quantum Dots by Controlled Positioning of Mn2+ Impurities

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• 作者：Nathan Grumbach ; Anna Rubin-Brusilovski ; Georgy I. Maikov ; Evgeny Tilchin ; Efrat Lifshitz
• 刊名：Journal of Physical Chemistry C
• 出版年：2013
• 出版时间：October 10, 2013
• 年：2013
• 卷：117
• 期：40
• 页码：21021-21027
• 全文大小：367K
• 年卷期：v.117,no.40(October 10, 2013)
• ISSN：1932-7455

文摘

Intentional inclusion of manganese ions (Mn²⁺) into colloidal quantum dots (CQDs) with precise positioning at a substitution lattice site provides a way to explore the interaction between photogenerated species (exciton, electron, hole) and Mn²⁺ spin states. We investigated the influence of Mn²⁺ impurity on the optical properties of CdTe/CdSe CQDs. Host CQDs exhibit a quasi-type-II characteristic, with asymmetric delocalization of the carriers over the entire core/shell structure. Mn²⁺ ions were precisely embedded either at the core or at the shell, using controlled layer-by-layer growth. Optical measurements carried out at cryogenic temperatures revealed a change in radiative lifetime, induced circular polarization, and energy split of exciton band-edge emission in the absence of an external magnetic field, when the Mn²⁺ ions were situated within the core. The results suggest the existence of a significant hole鈥揗n²⁺ exchange interaction and demonstrate a way to control band-edge optical properties in confined systems.