Application of RF discharge in oxygen to create highly oxidized metal layers

The radio frequency (RF) discharge in an oxygen atmosphere was used to produce metal oxide films. The high efficiency of the RF discharge technique for metal oxidation at room temperature was demonstrated for gold, silver and copper foils. Oxide films up to 10 nm in thickness were obtained. The produced oxide films were studied by X-ray photoelectron spectroscopy (XPS). The XPS data showed the formation of oxidised species: Cu²⁺, Ag¹⁺ and Au³⁺. Analysis of the oxygen species was performed using O1s spectra. For copper and silver foils, the formation of additional oxygen species apart from oxygen in the structure of oxides was shown. The reaction probability toward oxidation of carbon monoxide (CO) was estimated for all oxidised layers. It was established that gold and silver oxide films interacted with CO at room temperature, while cupric oxide showed high activity at temperature >353 K.