Optical Properties of CuO Studied by Spectroscopic Ellipsometry

Abstract

The real ( ε 1 ) and imaginary ( ε 2 ) parts of the dielectric function of polycrystalline samples of monoclinic CuO have been measured by spectroscopic ellipsometry in the 1.2–5.0-eV photon-energy range at room temperature. The CuO crystals having a grain size of the order of 1×1 mm 2 were successfully grown by a floating-zone melting technique. Dielectric-function spectra of polycrystalline CuO reveal distinct structures at energies of E 1 ∼1.6 eV, E 2 ∼2.0 eV, E 3 ∼2.6 eV and E 4 ∼3.4 eV. These spectra are analyzed on the basis of a harmonic oscillator approximation. Dielectric-related optical constants, such as the complex refractive index ( n * = n + i k ), absorption coefficient (α) and normal-incidence reflectivity ( R ), of CuO are also presented.