Optical properties of CuO studied by spectroscopic ellipsometry

The real (epsilon(1)) and imaginary (epsilon(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 Ix 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 similar to 1.6eV, E-2 similar to 2.0eV, E-3 similar to 2.6eV and E-4 similar to 3.4eV. These spectra are analyzed on the basis of a harmonic oscillator approximation. Dielectric-related optical constants, such as the complex refractive index (n* = n+ik), absorption coefficient (alpha) and normal-incidence reflectivity (R); of CuO are also presented.