Decoupling the effects of confinement and passivation on semiconductor quantum dots

Semiconductor (SC) quantum dots (QDs) have recently been fabricated by both chemical and plasma techniques for specific absorption and emission of light. Their optical properties are governed by the size of the QD and the chemistry of any passivation at their surface. Here, we decouple the effects o...

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Bibliographic Details
Published in:Physical chemistry chemical physics : PCCP 2016-07, Vol.18 (29), p.19765-19772
Main Authors: Rudd, Roya, Hall, Colin, Murphy, Peter J, Reece, Peter J, Charrault, Eric, Evans, Drew
Format: Article
Language:English
Subjects:
Confinement
Energy gaps (solid state)
Fluorination
Magnetron sputtering
Passivation
Quantum dots
Semiconductors
Silicon
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Summary:Semiconductor (SC) quantum dots (QDs) have recently been fabricated by both chemical and plasma techniques for specific absorption and emission of light. Their optical properties are governed by the size of the QD and the chemistry of any passivation at their surface. Here, we decouple the effects of confinement and passivation by utilising DC magnetron sputtering to fabricate SC QDs in a perfluorinated polyether oil. Very high band gaps are observed for fluorinated QDs with increasing levels of quantum confinement (from 4.2 to 4.6 eV for Si, and 2.5 to 3 eV for Ge), with a shift down to 3.4 eV for Si when oxygen is introduced to the passivation layer. In contrast, the fluorinated Si QDs display a constant UV photoluminescence (3.8 eV) irrespective of size. This ability to tune the size and passivation independently opens a new opportunity to extending the use of simple semiconductor QDs. Plasma synthesised Si QDs are deposited in liquids to decouple confinement and passivation effects on their optical properties.
ISSN:1463-9076
1463-9084
DOI:10.1039/c6cp03438a