Experimental and theoretical contributions to the determination of optical properties of synthetic paramelaconite

Paramelaconite (Cu4O3) is a metastable copper oxide that can be barely synthesised in “pure” form. In this study, the reactive magnetron sputtering process was used to deposit Cu4O3 films on silicon and glass substrates. The deposited films were characterised by X-ray diffraction (XRD), UV-visible-NIR spectroscopy and spectroscopic ellipsometry. For the first time, the refractive index and the extinction coefficient of Cu4O3 were evaluated. The experimental values obtained from spectroscopic ellipsometry were compared to those calculated by a self-consistent approach using the Wien2k code. A very good agreement was found between the two sets of values.