In situ Eu doping into AlxGa1−xN grown by organometallic vapor phase epitaxy to improve luminescence properties

•In situ Eu-doped AlGaN was grown by OMVPE.•Low-pressure is crucial condition for doping of optically active Eu ions.•The PL intensity of Al0.24Ga0.76N:Eu is 14 times higher than that in GaN:Eu.•The concentration of Eu2+ increases at Al compositions of higher than 0.24.•The amount of thermal quenching decreases at higher Al composition.

We have succeeded in situ Eu doping into AlxGa1−xN grown by organometallic vapor phase epitaxy and investigated the effects of the growth pressure and Al composition on the photoluminescence (PL) properties of Eu3+ ions. The intensity of red emission due to the 5D0–7F2 transition of Eu3+ ions decreased with increasing Al content in the case of growth at atmospheric pressure. The effect of the reactor pressure on the Eu concentration and Eu3+ PL properties showed that low-pressure growth is effective in increasing the Eu doping concentration and luminescence efficiency. The PL intensity increased with the Al composition and reached a maximum intensity at approximately x = 0.24. At Al compositions of higher than 0.24, X-ray absorption near-edge structure analysis revealed that the concentration of Eu2+ ions increased with increasing Al composition, leading to a reduction in the concentration of optically active Eu3+ ions.