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.     

Copper oxide particles produced by laser ablation in water

Laser ablation of copper metal in water was performed in order to obtain copper oxide particles. Scanning electron microscopy, energy dispersive X-ray fluorescence spectrometry, transmission electron microscopy, and electron diffraction were conducted in order to determine the size, shape and structure of the particles. The source of the O atoms in the copper oxide particles is the surrounding water molecules. The copper oxide particles obtained by laser ablation were both crystalline and amorphous. The crystalline particles were determined to be paramelaconite Cu₄O₃.