Synthesis of AlN: Eu²⁺ green phosphors by a simple direct nitridation method

Abstract

Eu-doped aluminum nitride phosphors were successfully prepared using simple direct nitridation of a metallic aluminum and Eu O powder mixture in flowing ammonia. AlN formed at reaction temperatures >900°C, and Eu transformed into the secondary oxide phase EuAl O in the nitridation condition. Phase pure AlN was obtained by post-heat treatment of the nitridated product at 1600°C for 3 h in a nitrogen atmosphere, with an Eu doping concentration < 0.5%. The phosphors exhibited broad green emission centered at 521 nm under 363 nm excitation. The luminescence of the phosphor was significantly influenced by the post-heat treatment temperature, which affected the dissolution of Eu , phase purity, crystallinity, and particle size of the AlN host.

Preparation of γ‐aluminum oxynitride phosphor with Eu doping by direct nitridation in ammonia and postannealing

“…00‐26‐1125) was detected. The Eu 3+ in the starting material Eu 2 O 3 could be reduced to Eu 2+ in the nitridation process, due to the reductive atmosphere of ammonia . Furthermore calcination led to the formation of EuAl 12 O 19 by reaction of alumina and EuO, that was the reason why alumina phase was absent in postcalcinated product.…”

“…Direct nitridation of metallic aluminum in N 2 and/or NH 3 gas is a commercial route to prepare AlN powders, which shows advantage of simplicity, low‐cost, and nontoxicity . Compared with the CRN method, direct nitridation eliminates the problem of carbon residue.…”

Direct observation of Eu atoms in AlN lattice and the first‐principles simulations

“…There have been experimental efforts to understand the luminescent properties of AlN‐based phosphors . It was demonstrated that Eu, Si co‐doped AlN phosphor shows a strong blue luminescence by UV or electron excitation .…”