Photoreflectance study of ion beam synthesized β-FeSi2

The photoreflectance spectra of ion beam synthesized beta-FeSi2 reveals a direct gap at 0.815 eV and are shown to agree with the band gap value obtained by photoluminescence once the adjustments for the temperature difference and trap related recombination effects are made. This provides very convincing evidence for intrinsic light emission from ion beam synthesized beta-FeSi2. Furthermore, we propose a simple model that helps to clarify the variety of inconsistent results obtained by optical absorption measurements. When the results of photoluminescence and photoreflectance are inserted into this model, we obtain good agreement with our measured optical absorption results. (C) 2002 American Institute of Physics.