| abstract |
The invention relates to an improved red light emitting material of the formula M 1−y A 1+x Si 4−x N 7−x−2y O x+2y :RE whereby M is selected out of the group comprising Ba, Sr, Ca, Mg or mixtures thereof, A is selected out of the group comprising Al, Ga, B or mixtures thereof, RE is selected out of the group comprising rare earth metals, Y, La, Sc or mixtures thereof and x is ≧0 and ≦1 and y is ≧0 and ≦0.2. This material is believed to crystallize in a novel structure type that comprises two individual lattice sites for rare earth metal incorporation, which leads to an improved lighting behaviour |