Photoluminescent and dielectric properties of Eu3+-doped LaAlO3 thin films fabricated by chemical solution deposition method

Photoluminescent (PL) and dielectric properties of La1−xEuxAlO3 thin films were investigated in terms of Eu doping content (x = 0, 0.02, 0.04, 0.06, 0.08, and 0.1) and annealing temperature. The La1−xEuxAlO3 thin films were prepared by a chemical solution deposition method and characterized by X-ray diffraction, field emission scanning electron microscopy, photoluminescence and dielectric measurement. The thin films were dense with a uniform thickness, and showed bright red-orange emissions, originated from the 5D0 → 7F2 and 5D0 → 7F1 transitions of Eu3+ ions. A stronger emission of 5D0 → 7F2 than that of 5D0 → 7F1 was attributed to Eu3+-doping induced structural distortion. The strongest PL intensity was observed in the thin films with a Eu3+-doping content x of 0.06, indicating the existence of concentration quenching effect of photoluminescence. Further lifetime study of photoluminescence indicated that the concentration quenching effect was due to the lifetime decrease of 5D0 → 7F1 and 5D0 → 7F2 transitions when Eu3+-doping content x increased. In addition, highly stable dielectric-bias electric field properties of Eu3+-doped LaAlO3 thin films have been confirmed. Our study suggests that Eu3+-doped LaAlO3 thin films have potential applications in integrated thin-film optoelectronic devices.