Crystal structures and luminescence properties of ALN-deficient Eu²⁺-activated Ca-α-SiAlON Phosphor

Eu²⁺-doped Ca-α-SiAlON phosphor was synthesized by normal pressure sintering with conventional tube furnace, and its crystal structures and luminescence properties were investigated. Eu²⁺-doped Ca-α-SiAlON phosphor exhibited an orange light peaking at 583 nm. During the annealing, some of the raw materials evaporated, which resulted in unreacted AlN in the final product. In order to obtain a final product with a single α-phase, we prepared samples with various AlN-deficient compositions, and we studied the effects on crystal structures and luminescence properties. For the sample with 15 mol% AlN-deficient composition, 18% enhancement of the intensity was obtained with the disappearance of excess AlN. In addition, the internal quantum efficiency (IQE) was measured using a specially designed integrating sphere, and 56.82% IQE was gained from Eu²⁺-doped Ca-α-SiAlON phosphor.