Influence of the surface termination on the light emission of crystalline silicon nanoparticles

Alexandre M P Botas, Rebecca J. Anthony, Jeslin Wu, David J. Rowe, Nuno J O Silva, Uwe Kortshagen, Rui N. Pereira, Rute A S Ferreira

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

The light emission properties of silicon crystalline nanoparticles (SiNPs) have been investigated using steady-state and time-resolved photoluminescence measurements carried out at 12 K and at room temperature. To enable a comparative study of the role of surface terminal groups on the optical properties, we investigated SiNPs-H ensembles with the same mean NP diameter but differing on the surface termination, namely organic-functionalized with 1-dodecene (SiNPs-C12) and H-terminated (SiNPs-H). We show that although the spectral dependence of the light emission is rather unaffected by surface termination, characterized by a single broad band peaking at ∼1.64 eV, both the exciton recombination lifetimes and quantum yields display a pronounced dependence on the surface termination. Exciton lifetimes and quantum yields are found to be significantly lower in SiNPs-H compared SiNPs-C12. This difference is due to distinct non-radiative recombination probabilities resulting from inter-NP exciton migration, which in SiNPs-C12 is inhibited by the energy barriers imposed by the bulky surface groups. The surface groups of organic-terminated SiPs are responsible for the inhibition of inter-NP exciton transfer, yielding a higher quantum yield compared to SiNPs-H. The surface oxidation of SiNPs-C12 leads to the appearance of a phenomenon of an exciton transference from to the Si core to oxide-related states that contribute to light emission. These excitons recombine radiatively, explaining why the emission quantum of the organic-terminated SiNPs is the same after surface oxidation of SiNPs-C12.

Original languageEnglish (US)
Article number325703
JournalNanotechnology
Volume27
Issue number32
DOIs
StatePublished - Jun 27 2016

Bibliographical note

Publisher Copyright:
© 2016 IOP Publishing Ltd.

Keywords

  • core-shell silicon nanoparticles
  • energy transfer
  • exciton migration
  • nonthermal plasma reactor
  • photoluminescence
  • quantum yield

How much support was provided by MRSEC?

  • Partial

Reporting period for MRSEC

  • Period 3

PubMed: MeSH publication types

  • Journal Article

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