Preparation of Aluminum Oxynitride by Nitridation of a Precursor Derived from Aluminum–Glycine Gel and the Effects of the Presence of Europium

Abstract

Spinel‐type AlON, Al2.75□0.25O3.74N0.26, was obtained by ammonia nitridation of an oxide precursor prepared by peptizing a glycine gel with aluminum nitrate. To achieve crystallization, the nitrided product had to be annealed at 1500°C for 10 min in flowing nitrogen. The use of glycine instead of citric acid was important for obtaining a white product without residual carbon. A similar preparation method was used for adding small amounts of europium below 10 mol%. A strong blue emission was observed for products ranging from 0.5 to 3.0 mol% Eu doping. The product with 0.5 mol% doping had a maximum emission intensity at 400 nm for an excitation of 254 nm. The products with 1 and 3 mol% doping showed double maxima at 475 and 520 nm. These three emissions were due to the presence of divalent europium in the EuAl12O19 magnetoplumbite‐like aluminum oxynitride impurity mixed with the AlON spinel major phase. The 1 mol% Eu‐doped product exhibited expanded hexagonal lattice parameters (a=0.5591 and c=2.236 nm) compared with the values for EuAl12O19 magnetoplumbite itself, observed in the 7.7 mol%‐doped product without any strong emission. The above spectrum change was discussed in relation to the coordination around Eu2+.