Photoluminescence and Raman spectroscopy of Ce3+ doped Y3Al5O12 single crystalline films grown onto Y3Al5O12 and Lu3Al5O12 substrates

Raman spectroscopy, high spectral resolution luminescence, and X-ray diffraction techniques were employed to study two Ce³⁺ doped Y₃Al₅O₁₂ single crystalline films grown by liquid phase epitaxy method onto Y₃Al₅O₁₂ and Lu₃Al₅O₁₂ single crystal substrates. Optical spectra were obtained with a micrometer step along the cross-sections of epitaxial structures, allowing excellent differentiation of the film, the transition layer, and the substrate of each sample. X-ray measurements demonstrate the mismatch between the lattice constants of the Y₃Al₅O₁₂:Ce³⁺ film and its Lu₃Al₅O₁₂ substrate, an effect related to different compositions. Consequently, the film grown onto Lu₃Al₅O₁₂ exhibits higher residual stresses than its counterpart grown onto Y₃Al₅O₁₂. This was confirmed by a mutual comparison of the Raman bands positions of the films. The luminescence spectra of both samples consist mainly of cerium 5d-4f emission, the intensity of which allows for additional study of epitaxial cross section and estimation of the size of transition layer.