Plasma synthesis and liquid-phase surface passivation of brightly luminescent Si nanocrystals

L. Mangolini, D. Jurbergs, E. Rogojina, U. Kortshagen

Research output: Contribution to journalArticlepeer-review

90 Scopus citations

Abstract

While silicon's optical properties are improved at the nanoscale, they also become highly sensitive to the properties of the surfaces and interfaces of silicon nanostructures. For instance, while reported quantum yields for photoluminescence of silicon quantum dots covered by a native oxide are often in the few percent range, quantum yields as high as 30% have been found in quantum dots whose surfaces were passivated by covalently bonded organic molecules. In this paper, we describe an approach that is based on the gas phase synthesis of silicon quantum dots in a nonthermal plasma, and the subsequent organic surface passivation in the liquid phase. Nanocrystals are formed within a few milliseconds with a high mass yield in a nonthermal plasma. Various organic ligands such as octadecene, dodecence, and styrene are grafted onto the nanocrystal surfaces in a reaction known as hydrosilylation. Materials are characterized through transmission electron microscopy, atomic force microscopy, and fluorescence measurements. The particle size distributions are found to be relatively monodisperse and are well controllable through the plasma process parameters. Photoluminescence quantum yields as high as 60-70% have been achieved for particles luminescing in the red range of the visible spectrum.

Original languageEnglish (US)
Pages (from-to)327-334
Number of pages8
JournalJournal of Luminescence
Volume121
Issue number2 SPEC. ISS.
DOIs
StatePublished - Dec 2006

Bibliographical note

Funding Information:
This work was supported by the National Science Foundation under award DMI-0556163. Partial support was provided by the MRSEC Program of the National Science Foundation under Award Number DMR-0212302.

Keywords

  • Organic surface passivation
  • Photoluminescence
  • Silicon quantum dot

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