Impact of AlGaN on luminescence capability of rare-earth ions in AlGaN

Effects of AlN molar fraction on the luminescence properties of rare-earth elements (RE) impurities of Eu and Tb in AlxGa1−xN (x = 0–1) have been investigated using cathodoluminescence and time-resolved photoluminescence. Rutherford backscattering and extended X-ray absorption fine-structure analysis reveal that the implanted Eu atom is on the group-III site. PL intensity due to inner-shell transitions of RE increases with AlN molar fraction and tends to saturate for higher fraction of AlN. Thermal quenching of PL intensity became very small with the increase of Al contents. Strong PL was observed even at 400 K in case of Eu-implanted samples with high Al content. The time-resolved PL confirmed that the improvement of PL capability is caused by the increase of energy transfer efficiency/active RE site and the reduction of energy-back-transfer process.