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Title
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Incorporation and localization of substitutional ions in cubic ZnS quantum dots
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Author
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Abstract
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| Multifrequency electron paramagnetic resonance (EPR) and high resolution transmission electron microscopy (HRTEM) investigations were performed on small (2 nm) cubic ZnS nanocrystals (quantum dotsQDs) doped with 0.2% mol Mn2+, self-assembled into a mesoporous structure. The EPR data analysis shows that the substitutional Mn2+ ions are localized at Zn2+ sites subjected to a local axial lattice distortion, resulting in the observed zero-field-splitting parameter |D|=41×10−4 cm−1. The local distortion is attributed to the presence in the second shell of ligands of a stacking fault or twin, which alters the normal stacking sequence of the cubic structure. The HRTEM results confirm the presence of such extended planar defects in a large percentage of the investigated QDs, which makes possible the proposed substitutional Mn2+ impurity ions localization model. Based on these results it is suggested that the high doping levels of Mn2+ ions observed in cubic ZnS and possible in other II-VI semiconductor QDs prepared at low temperatures can be explained by the assistance of the extended lattice defects in the impurities incorporation. |
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Language
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English
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Source (journal)
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Physical review : B : condensed matter and materials physics. - Lancaster, Pa, 1998 - 2015
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Publication
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Lancaster, Pa
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2010
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ISSN
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1098-0121
[print]
1550-235X
[online]
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DOI
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10.1103/PHYSREVB.81.035336
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Volume/pages
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81
:3
(2010)
, p. 035336,1-035336,6
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ISI
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000277970900007
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Full text (Publisher's DOI)
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Full text (open access)
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