Resonant energy transfer from nanocrystal Si to β-FeSi₂ in hybrid Si/β-FeSi₂ film

The photoluminescence (PL) characteristics of hybrid β-FeSi₂/Si and pure β-FeSi₂ films fabricated by pulsed laser deposition at 20 K are investigated. The intensity of the 1.54-μm PL from the former is enhanced, but the enhancement vanishes when the excitation wavelength is larger than the widened band gap of Si nanocrystal. Time-resolved PL decay measurements reveal that the lifetime of the photo-excited carriers in the hybrid β-FeSi₂/Si film is longer than that in the pure β-FeSi₂ film, providing evidence that the PL enhancement results from the resonant charge transfer from nanocrystalline Si to β-FeSi₂.