Highly Efficient and Thermally Stable Blue-Emitting AlN:Eu²⁺ Phosphor for Ultraviolet White Light-Emitting Diodes

An Eu 2+ -activated AlN phosphor was synthesized by firing the powder mixture of AlN, α-Si 3 N 4, and Eu 2 O 3 at 1500−2050 °C for 4 h under 1.0 MPa N 2 . The phase purity, photoluminescent properties, thermal quenching, and quantum efficiency of the fired samples were investigated. A single AlN wurtzite phase was formed at low doping concentrations of Eu 2+ (≤0.1 mol %) and Si (≤2.2 mol %). The introduction of Si is essential for the solubility of Eu 2+ in the AlN lattice. Intense blue luminescence with a peak emission wavelength of 465 nm was observed in AlN:Eu 2+, when Si was doped simultaneously. This blue phosphor shows a small thermal quenching, retaining the luminance of 90% at 150 °C. The absorption and external quantum efficiencies of AlN:Eu 2+ are 63%μ and 46% upon 365 nm excitation, respectively. These results indicate that AlN:Eu 2+ has great potential as a blue phosphor for white light-emitting diodes (LEDs) utilizing UV chips as the light source.