Synthesis, structural and spectral properties of rare earth-doped YAG nanoparticles to be used in laser system / Hanan Fawzy Ali Omar Sharafeldin ; Supervised Mohamed Atta Khedr

Thesis (Ph.D.) - Cairo University - National Institute of Laser Enhanced Sciences (NILES) - Department of Laser Sciences and Interactions

This work deals with the structural and optical properties of samarium (Sm) and cerium (Ce) singly and co-doped in yttrium aluminum garnet (YAG) nanocrystals and ceramic forms. The nanocrystalline samples have been prepared via co-precipitation method then transformed to bulk ceramic by sintering process using Spark Plasma Sintering (SPS) technique. X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM) are used to characterize the crystal structure of the nanocrystals.The micro-grains of the obtained ceramic have been demonstrated by scanning electron microscope (SEM).The effect of calcination temperature on the formation of the crystalline phase of the prepared powder has been studied.The optical properties of the prepared samples (nanocrystals and ceramic) have been investigated in details using the photoluminescence (PL),the photoluminescence excitation (PLE), cathodoluminescence (CL),Time resolved photoluminescence (TRPL) spectroscopies. In addition, energy transfer mechanism between Ce and Sm ions in co-doped samples were evidenced. Tuning between the spectral features of Ce and Sm is obtained and discussed in light of spectral overlapping between the excitation states in both ions. Moreover, in ceramic samples, controlling the relative PL spectral contributions either from the host defects or cerium ions with the spectral lines from Sm ions has been achieved by changing the excitation wavelengths

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