Structural and photoluminescence properties of Y<inf>2</inf>O<inf>3</inf> and Y<inf>2</inf>O<inf>3</inf>:Ln³⁺ (Ln = Eu, Er, Ho) films synthesized by plasma electrolytic oxidation of yttrium substrate

Abstract

Plasma electrolytic oxidation (PEO) of yttrium is performed for the first time and is shown that Y2O3 and trivalent rare-earth ions (Eu3+, Er3+ or Ho3+) doped Y2O3 films can be formed by PEO in alkaline electrolyte without or with addition of rare-earth oxide particles (Eu2O3, Er2O3 or Ho2O3), respectively. The elements present in PEO micro-discharges were identified using optical emission spectroscopy technique. The gas plasma temperature of (3000 ± 300) K was estimated from the intensity distribution within a part of an OH spectrum. The morphology, chemical composition, crystal structure, formation process and photoluminescence (PL) properties of formed films were investigated. Diffraction patterns of formed films show well pronounced reflections inherent to pure cubic phase of Y2O3. PL characterization of Y2O3 and Y2O3:Ln3+ (Ln = Eu, Er, Ho) films is performed through excitation and emission spectra. An intense red PL emission was observed from the Y2O3:Eu3+ and a green emission was observed from Y2O3:Er3+ and Y2O3:Ho3+ films.