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

• YAG:Ce SCF/YAG SC and YAG:Ce SCF/LuAG SC were grown using LPE method. • Sample cross-section allowed to obtain Raman signal from SCF, TL and substrate. • Raman and luminescence study proved existence of transition layer (TL). • Spectroscopy study confirmed a gradual stress relaxation mechanism occurring in TL. Raman spectroscopy, high spectral resolution luminescence, and X-ray diffraction techniques were employed to study two Ce 3+ doped Y 3 Al 5 O 12 single crystalline films grown by liquid phase epitaxy method onto Y 3 Al 5 O 12 and Lu 3 Al 5 O 12 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 Y 3 Al 5 O 12 :Ce 3+ film and its Lu 3 Al 5 O 12 substrate, an effect related to different compositions. Consequently, the film grown onto Lu 3 Al 5 O 12 exhibits higher residual stresses than its counterpart grown onto Y 3 Al 5 O 12 . 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.