Visible and ultraviolet optical properties of single-crystal and polycrystalline hematite measured by spectroscopic ellipsometry

The optical properties of single-crystal and polycrystalline hematite (α-Fe2O3), which is an absorbing uniaxial material, have been measured over the visible and ultraviolet spectra (1.6–4.8 eV) by ellipsometric spectroscopy. Three Lorentz oscillators are observed in polycrystalline α-Fe2O3 at 2.2, 2.95, and 3.85 eV. The half-widths are ~0.2, ~0.7, and ~0.4 eV, respectively. In single-crystal α-Fe2O3, the peak in ∊2e is shifted to 2.8 eV, compared with 2.95 eV for the ∊2∘, which is the same as in the polycrystalline spectrum.