The origin of bimodal luminescence of beta-SiAlON:Eu2+ phosphors as revealed by fluorescence microscopy and cathodoluminescence analysis

<span lang="EN-US" style="font-family: &quot;Calibri&quot;,&quot;sans-serif&quot;; font-size: 10.5pt; mso-bidi-font-size: 11.0pt; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋体; mso-fareast-theme-font: minor-fareast; mso-hansi-theme-font: minor-latin; mso-bidi-font-family: &quot;Times New Roman&quot;; mso-bidi-theme-font: minor-bidi; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;"><font color="#000000">Eu2+-doped SiAlON phosphors with the composition of EuxSi6-zAlzOzN8-z(0.5 &lt;= z &lt;= 3) at a fixed x = 0.01 were synthesized by the gas pressure sintering method. Dependence of luminescence properties on the phase compositions in beta-SiAlON:Eu2+ phosphors has been examined via fluorescence microscope and scanning electron microscope equipped with a cathodoluminescence spectrometer and an energy dispersive spectrometer. Bimodal emission (green and violet) from beta-SiAlON phase is observed in the samples with z &gt;= 2, indicating co-existence of two different kinds of coordination for Eu2+ ions in the host lattice. (C) 2013 Elsevier Ltd. All rights reserved.</font></span