Experimental investigation of the band edge anisotropy of the β-FeSi2 semiconductor

Samples prepared by ion-beam synthesis are studied. A two-step 56 Fe + ion implantation process was performed on n-type Si wafers with (100) orientation. Subsequently, the samples, implanted with the same dose and energies, were subjected to rapid thermal annealing at two different temperatures – 800 °C and 900 °C for the same time – 90 s. A remarkable difference in the infrared spectra and in the refractive index dispersions near the band edge of samples annealed at different temperatures was found. The behaviour of the optical properties was related to different morphology of the samples.