Intense Photoluminescence in Erbium-Ion-Implanted Lithium Niobate Thin Films and Its Interplay with Lattice Defects

Erbium-doped lithium niobate on insulator (Er-LNOI) has attracted significant attention for its potential in integrated photonics and quantum applications due to its efficient 1540 nm emission in the telecom band. In this work, the lattice damage and infrared photoluminescence of Er-LNOI fabricated via Er ion implantation and subsequent thermal annealing is investigated. Damage profiles are analyzed using Rutherford backscattering spectrometry in channeling mode (RBS/C), revealing the formation of an amorphous layer during ion implantation. However, re-crystallization into an Er-doped LNOI single crystal occurs with some remaining dislocation loops after annealing. Photoluminescence measurements at room temperature demonstrate intense infrared emission with no evidence of Er clustering and concentration quenching up to an Er fluence of 2.63 × 10¹⁵ ions cm². Power- and temperature-dependent PL spectra suggest stable emission and distinct thermal quenching mechanisms for the two Stark-split transitions. The results confirm the effective optical activation of single crystalline Er-LNOI and highlight its promise for on-chip light sources and active photonic devices.