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Keywords:

  • iron silicide;
  • infrared photoluminescence;
  • nanocrystal;
  • phase transition

Abstract

We have systematically investigated photoluminescence (PL) properties of β-phase nanocrystals which are formed by a phase transition from metastable γ-FeSi2 with a Fluorite structure to β-FeSi2, and succeeded in enhancement of the PL intensity in the optimum conditions of double annealing process. For the PL enhancement, the time of postannealing at 800 °C is dominated by the time of the preannealing at 400 or 500 °C which is related to amount of the γ-phase. After discussing some possible factors, we speculate that the PL enhancement observed in this study may be attributed mainly to improvement of the interface condition between the nanocrystal and Si, because the crystallographic epitaxial relationship among the phases, Si(111)//γ(111)//β(202)/(220) can be maintained during precipitation of the nanocrystal on Si(111). (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)