Structural and optical properties of beta-FeSi2 phase prepared by ion beam synthesis

Semiconducting iron disilicide (β-FeSi2) was prepared by ion beam synthesis (IBS) in (111)Si P-type by implantation at 440 ˚C of 195 KeV Fe ions with a dose of 2.1017 Fe+/cm2 followed by annealing in a N2 atmosphere at 900 ˚C for 4 h. Characterization of samples included Rutherford backscattering spectrometry (RBS), X-ray diffraction (XRD) pole figure, and Raman spectroscopy. A mixture of β-FeSi2 and α-FeSi2 was observed in the as-implanted state. A Photoluminescence (PL) measurement at 12K indicates the luminescence peak at the energy of about 0.81 eV corresponding to the band gap energy of β-FeSi2 phase.