Tunable band gap emission and surface passivation of germanium nanocrystals synthesized in the gas phase

Lance M. Wheeler, Laszlo M. Levij, Uwe R. Kortshagen

Research output: Contribution to journalArticlepeer-review

39 Scopus citations

Abstract

The narrow bulk band gap and large exciton Bohr radius of germanium (Ge) make it an attractive material for optoelectronics utilizing band-gap-tunable photoluminescence (PL). However, realization of PL due to quantum confinement remains scarcely reported. Instead, PL is often observed from surface trap states and is independent of nanocrystal (NC) size. Here, we demonstrate tunable band gap PL by chemically passivating the Ge NC surface. The exchange of native Ge-Cl surface groups with alkyl groups using Grignard reagents leads to the first instance of tunable band gap emission from free-standing Ge NCs synthesized in the gas phase. Ge NCs between 4.8 and 10.2 nm in diameter exhibit near-infrared emission featuring spectral line widths that are at least a factor of 2 narrower than any previous report.

Original languageEnglish (US)
Pages (from-to)3392-3396
Number of pages5
JournalJournal of Physical Chemistry Letters
Volume4
Issue number20
DOIs
StatePublished - Oct 17 2013

Keywords

  • near-infrared
  • photoluminescence
  • plasma synthesis
  • quantum confinement
  • quantum dot

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