Quantum confinement in germanium nanocrystal thin films

Zachary C. Holman, Uwe R. Kortshagen

Research output: Contribution to journalLetter

11 Scopus citations

Abstract

Thin films of semiconductor nanocrystals with tunable optical properties are promising materials for new device applications, but progress has been slow for group IV materials. We report absorption measurements near the absorption edge of thin films of germanium nanocrystals synthesized in a plasma and impacted onto substrates. Band gaps extracted from the absorption data vary from the near-bulk value of 0.73 eV for 9.0 nm nanocrystals to over 1.0 eV for 4.7 nm nanocrystals. These values are comparable to those reported for isolated, non-interacting germanium nanocrystals, indicating minimal loss of quantum confinement upon dense film formation. (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) In this Letter, the optical band gaps of dense films of germanium nanocrystals were determined from absorption spectra. By decreasing the constituent nanocrystal size from 9 nm to below 5 nm, the film band gap can be controllably tuned from 0.73 to over 1.0 eV. These values are comparable to those reported for isolated, non-interacting germanium nanocrystals, indicating that device-relevant films can be deposited without loss of quantum confinement.

Original languageEnglish (US)
Pages (from-to)110-112
Number of pages3
JournalPhysica Status Solidi - Rapid Research Letters
Volume5
Issue number3
DOIs
StatePublished - Mar 1 2011
Externally publishedYes

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Keywords

  • Absorption
  • Band gap
  • Germanium
  • Nanocrystals

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics

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