In Situ Monitoring of Pulsed Laser Annealing of Eu-Doped Oxide Thin Films

Eu³⁺-doped oxide thin films possess a great potential for several emerging applications in optics, optoelectronics, and sensors. The applications demand maximizing Eu³⁺ photoluminescence response. Eu-doped ZnO, TiO_2, and Lu₂O₃ thin films were deposited by Pulsed Laser Deposition (PLD). Pulsed UV Laser Annealing (PLA) was utilized to modify the properties of the films. In situ monitoring of the evolution of optical properties (photoluminescence and transmittance) at PLA was realized to optimize efficiently PLA conditions. The changes in optical properties were related to structural, microstructural, and surface properties characterized by X-ray diffraction (XRD) and atomic force microscopy (AFM). The substantial increase of Eu³⁺ emission was observed for all annealed materials. PLA induces crystallization of TiO₂ and Lu₂O₃ amorphous matrix, while in the case of already nanocrystalline ZnO, rather surface smoothening0related grains' coalescence was observed.