SPECTRAL SWITCHING OF TYPE-II QUANTUM DOTS BY CHARGING
SCIE
SCOPUS
- Title
- SPECTRAL SWITCHING OF TYPE-II QUANTUM DOTS BY CHARGING
- Authors
- Bang, J; Chon, B; Won, N; Nam, J; Joo, T; Kim, S
- Date Issued
- 2009-04-23
- Publisher
- AMER CHEMICAL SOC
- Abstract
- We report photoluminescence (PL) spectral switching of quantum dots (QDs) by chemically controlling transfers of electrons in and out of the type-II heterostructures. When electron charged, CdTe/CdSe (core/shell) QDs show huge PL blue shifts (up to similar to 100 nm) whereas PL of CdSe/CdTe (core/shell) QDs red-shifts. We demonstrate reversible spectral switching of type-II QDs by repeated charging and neutralization processes. The PL spectral shifts are due to the interactions between injected spectrator electrons and type-II character excitons. Electron charged CdTe/CdSe QDs show PL blue shifts because of the strong repulsions between the shell-localized excitonic electrons and injected spectrator electrons. It is opposite for CdSe/CdTe QDs, where injected electrons in surface states attract the holes in the shells. We investigate the interactions of spectrator electrons and excitons as varying the dimensions of type-II QDs. We also compare the type-II QDs with type-I QDs such as CdSe, CdTe, and CdTeSe alloyed QDs. We showcase unique optical properties of charged type-II QDs, which have many potential applications such as electro-optic modulators.
- URI
- https://oasis.postech.ac.kr/handle/2014.oak/27942
- DOI
- 10.1021/JP900530A
- ISSN
- 1932-7447
- Article Type
- Article
- Citation
- JOURNAL OF PHYSICAL CHEMISTRY C, vol. 113, no. 16, page. 6320 - 6323, 2009-04-23
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