Synthesis, crystal structure and photoluminescence of a new Eu-doped Sr containing sialon (Sr0.94Eu0.06)(Al0.3Si0.7)4(N0.8O0.2)6

Abstract

Colorless transparent platelet single crystals of a novel Eu2+-doped strontium silicon aluminum oxynitride, (Sr0.94Eu0.06)(Al0.3Si0.7)4(N0.8O0.2)6, were prepared at 1800°C and 0.92MPa of N2. Fundamental reflections of electron and X-ray diffraction of the crystals were indexed with a face-centered orthorhombic unit cell (a=5.8061(5)Å, b=37.762(3)Å, c=9.5936(9)Å). Diffuse streaks elongated in the b-axis direction were observed around the fundamental reflections hkl with h=2n+1 of the electron and X-ray diffraction, indicating stacking faults of (010)[100]/2. A crystal structure model without the stacking faults was obtained using the X-ray diffraction data of the fundamental reflections with the space group Fdd2. A SiN4-tetrahedron double layer of [SiN2]2 and a Sr/Eu double layer of [(Sr0.94Eu0.06)Al1.2Si0.8N0.8 O1.2]2 are stacked alternately along the b-axis direction. The title compound showed an emission with a peak wavelength of 490nm under 334nm excitation at room temperature.