Analysis of the dielectric constants of the Ag 2O film by spectroscopic ellipsometry and single-oscillator model

Abstract

Ag 2O film was prepared on glass substrate by direct current reactive magnetron sputtering under a careful control of the preparation parameters. The analysis of the dielectric constants of the Ag 2O film related to the optical properties was conducted by spectroscopic ellipsometry (SE) and single-oscillator model. The dielectric constants were fitted in terms of general oscillator model (a model combined with three Tauc–Lorentz oscillator models) by using the measured SE data. Refractive-index dispersion data below the interband absorption edge of the Ag 2O film were analyzed using a single oscillator fit of the form n 2 − 1 = E d E 0 / ( E 0 2 − ℏ 2 ω 2 ) proposed by Wemple and DiDomenico, where ℏ ω is the photon energy, E 0 is the single oscillator energy, and E d is the dispersion energy. The optical energy gap of approximately 2.32 eV was fitted by single oscillator model, which was in good agreement with that in terms of Tauc relation. The fitted dispersion energy E d of approximately 20.28 eV determined the parameter β of approximately 0.32 by a simple empirical relationship E d=βN cZ aN e , which indicated that Ag 2O film falls into covalent class. Additionally, the band gap parameter E a and plasma frequency ℏ ω p fitted were 1.16 and 4.85 eV, respectively.