Epitaxial growth and characterization of Si-based light-emitting Si/β-FeSi2 film/Si double heterostructures on Si(001) substrates by molecular beam epitaxy

Si/β-FeSi2/Si (SFS) heterostructures were grown epitaxially on Si(001) by reactive deposition epitaxy (RDE) for β-FeSi2 and by molecular beam epitaxy (MBE) for Si. Distinct 1.54-μm photoluminescence was observed at 77 K for SFS with a β-FeSi2 thickness ranging from 5 to 10 nm. When the thickness of the β-FeSi2 layer was increased up to 40 nm, the PL intensity of β-FeSi2 decreased and the full-width at half maximum (FWHM) of the PL peak increased. Reflection high-energy electron diffraction observation revealed that the Si overlayer has a tendency to form polycrystalline structures with the increase of β-FeSi2 thickness. The degradation of PL was also observed for samples annealed at 900 °C.