Luminescence spectroscopy of europium doped gallium nitride powder prepared by a Na flux method

The red emission properties of Eu doped gallium nitride (GaN) powder prepared by a Na flux method were characterized by time‐resolved photoluminescence (PL) and site‐selective PL excitation studies. Under above‐gap excitation (325 nm), Eu 3+ doped GaN powders exhibited bright red luminescence at ∼622 nm ( 5 D 0  →  7 F 2 transition). The room‐temperature emission lifetime was determined to be ∼242 µs and increased only slightly at 10 K with a value of ∼252 µs. At the same time, the integrated Eu 3+ PL intensity was quenched by a factor of ∼20 for the temperature range from 10 to 300 K. Low temperature PL excitation studies in the region of the 7 F 0  →  5 D 0 transition of Eu 3+ ions indicated the existence of multiple Eu 3+ centers with distinct excitation and emission properties in GaN:Eu powder.