Cathodoluminescence properties of blue emitting Eu ²⁺-doped AlN -polytypoids for field-emission displays

Eu²⁺-doped AlN-polytypoids (8H, 15R, 12H, and 21R) were successfully synthesized by nitrogen-gas-pressure sintering. The phosphors show intense blue emissions under the electron beam excitation. All the polytypoid phosphors exhibit relatively a smaller degradation in luminance and a higher thermal stability in comparison to the oxide counterparts. Among the polytypoids, 12H has no luminance saturation, and shows a brightness of 40 cd/m² at 3 kV and 100 μA. These results indicate that Eu ²⁺-doped AlN-polytypoids could also be used as blue phosphors for FEDs.