Optical transition properties of β-FeSi₂ film

Optical transition of properties of β-FeSi₂ film have been investigated by optical transmittance absorption measurement, spectroscopic ellipsometry and reflectivity. Optical transmittance absorption measurement ranging from 0.5 to 1.1 eV revealed the direct transition at E₀=0.84 eV, while absorption curve obtained from the spectroscopic measurement in the range of 1.5-4.5 eV implied additional transition at E'=1.05 eV, it is suggested that such additional transition originates from spin-orbit splitting at Γ (center of Brillouin's zone). Reflectivity goes to the maximum value near E_g, indicating that the joint density of states in the transition at E_g is very high. Another peak which is related with the transition at E' was also observed in the reflectivity spectra.