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Physical Sciences and Mathematics Commons

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Astrophysics and Astronomy

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Bowling Green State University

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2008

Articles 1 - 2 of 2

Full-Text Articles in Physical Sciences and Mathematics

Composition-Tunable Properties Of Cdsxte1-X Alloy Nanocrystals, Nilanka P. Gurusinghe, Nishshanka N. Hewa-Kasakarage, Mikhail Zamkov Aug 2008

Composition-Tunable Properties Of Cdsxte1-X Alloy Nanocrystals, Nilanka P. Gurusinghe, Nishshanka N. Hewa-Kasakarage, Mikhail Zamkov

Physics and Astronomy Faculty Publications

Ternary CdSxTe1-x semiconductor quantum dots with both homogeneous and gradient composition have been fabricated via pyrolysis of organometallic precursors. The nanocrystal structure, size, and composition were characterized by UV-visible absorption and fluorescence spectroscopy, transmission electron microscopy, energy-dispersive X-ray elemental analysis, and X-ray diffractrometry. It was found that the band gap of homogeneously alloyed CdSxTe1-x is highly nonlinear with the crystalline composition, which was evidenced by a significant red-shift in the fluorescence of these nanocrystals with respect to the emission wavelength of their CdS and CdTe binary compounds. This effect, also known as optical bowing, seems to be enhanced in CdSxTe1-x …


Synthesis And Characterization Of Type Ii Znse/Cds Core/Shell Nanocrystals, Alexander Nemchinov, Maria Kirsanova, Nishshanka N. Hewa-Kasakarage, Mikhail Zamkov Jun 2008

Synthesis And Characterization Of Type Ii Znse/Cds Core/Shell Nanocrystals, Alexander Nemchinov, Maria Kirsanova, Nishshanka N. Hewa-Kasakarage, Mikhail Zamkov

Physics and Astronomy Faculty Publications

High-quality ZnSe/CdS core/shell nanocrystals, exhibiting a type II carrier localization regime, were fabricated via a traditional pyrolysis of organometallic precursors. The two-step synthesis involved fabrication of 4.5-6 nm ZnSe seeds followed by a subsequent deposition of the CdS shell. An efficient spatial separation of electrons and holes between the core and the shell was observed for heterostructures containing more than three monolayers of CdS, which was primarily evidenced by the spatially indirect emission tunable from 480 to 610 nm for a fixed core diameter. Because of a large (type II) offset of band edges at the core/shell interface, fabricated nanocrystals …