Synthesis and luminescence properties of rare-earth ion doped alkaline silicon oxynitride

Abstract

We investigated the conditions for the syntheses of BaSi₆ON₈ and Ba_4-xCa_xSi₆ON₁₀ through the solid-state reaction. The BaSi₆ON₈ was prepared by the solid-state reaction of BaCO₃ and Si₃N₄ with the molar ratio of (Si/(Ba+RE))=6.0; RE= Eu or Ce) at a temperature between 1650 and 1800 deg C for 2 h. On the other hand, Ba_4-xCa_xSi₆ON₁₀ was obtained when the mixture of starting materials, i.e., BaN_x, Ca₃N₂, SiO₂ and Si₃N₄ with x value of 2.2 was heated at a temperature 1450 deg C for 2 h in N₂-H₂ (N₂90%-H₂10%) atmosphere. The excitation and emission wavelengths of 2 mol% Eu²⁺-doped BaSi₆ON₈ were 370 and 508 nm, respectively, whereas for 3 mol%Eu²⁺-doped Ba_4-xCa_xSi₆ON₁₀ were found to be 530 and 648 nm, respectively.