AlN:Eu keramiku spektrālās īpašības un luminiscences mehānismi

Abstract

The current study was dedicated to exploring luminescence of AlN ceramics with europium admixture (AlN:Eu). Photoluminescence as well as its excitation spectra, taken at wide spectral intervals, at different temperatures and environments (vacuum and air), were used to study the optical properties of the material.AlN:Eu ceramics were dominated by the well-known red and green luminescence of Eu ions, around 530 nm and 600 nm, which could be excited by both visible and UV light. In ceramics with a higher Eu content, more intense luminosity of the bands associated with europium, especially around 530 nm, was observed, while, contrary to lower concentration sample, no luminescence bands between 440 nm and 500 nm were observed. The differences, most likely, can be explained by the different structure of the material at different concentrations of admixture. At excitation of samples with 340 nm light, mutually different changes in 530 nm luminescence intensity were also observed when temperatures of materials were lowered: at higher Eu concentrations, the intensity increased, whereas at lower concentrations – decreased. The analysis of the experimental results allows to propose several mechanisms that are responsible for the luminescence of the considered materials, consisting mainly of the emission of defects related to Eu ions. They include both intracenter and recombination mechanisms, whose contribution to luminescence depends on the spectral structure of the excitation light. The obtained data can be used for further research and development of new persistent luminescence materials.