Stress State and Cathodoluminescence Properties of Sm 3+ /Eu 3+ Co‐Doped AlN Thin Films

Sm 3+ single‐doped, Eu 3+ single‐doped,and Sm 3+ /Eu 3+ co‐doped AlN thin films are prepared by ion implantation for the first time. X‐ray diffraction and Raman spectroscopy show that lattice damage intensifies with implantation fluence, while residual compressive stress in co‐doped films increases monotonically with Eu 3+ fluence. Cathodoluminescence (CL) spectra show that the Sm 3+ single‐doped films reach maximum emission intensity at 5 × 10 14 at/cm 2 , beyond which concentration quenching occurs. In the co‐doped films, weakening of the Sm 3+ emission accompanies a marked enhancement of the Eu 3+ emission, indicating nonradiative resonant energy transfer from Sm 3+ ( 4 G 5/2 → 6 H 7/2 ) to Eu 3+ ( 5 D 0 → 7 F 2 ). Reisfeld analysis suggests that the energy transfer within the AlN matrix is most likely mediated by coexisting dipole–dipole and dipole–quadrupole electric multipolar interactions rather than a single dominant term. Chromaticity analysis demonstrates that increasing the Sm 3+ fluence shifts the single‐doped emission from bluish–white to orange–red, raising the color purity from 41.6% to 58.8%. For the co‐doped films, the emission tunes from orange‐red to pure red, and an optimal color purity of 85.8% is achieved at Sm 3+ and Eu 3+ fluences of 1 × 10 14 and 5 × 10 14 at/cm 2 , respectively. These results confirm that precise control of the Sm 3+ /Eu 3+ ratio synergistically optimizes the chromaticity and color purity of red AlN emission.