Optical Constants of β-FeSi_2 Film on Si Substrate Obtained from Transmittance and Reflectance Data and Origin of Urbach Tail

摘要

β-FeSi_2 film was prepared on a Si(001) substrate by molecular beam epitaxy using an Fe source. The crystallinity and crystallographic orientation of β-FeSi_2 film on the Si(001) substrate was characterized by X-ray diffraction analysis. Optical constants and the onset of the band-edge absorption of β-FeSi_2 film on the Si(001) substrate were evaluated by solving simultaneous equations of reflectance and transmittance data. The extinction coefficient calculated using simultaneous equations showed abrupt absorption at the band-edge.