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    Broadband luminescence of Cu nanoparticles fabricated in SiO2 by ion implantation
    (PERGAMON-ELSEVIER SCIENCE LTD, 2016) Truong Khang Nguyen; Le, Khai Q.; Canimoglu, Adil; Can, Nurdogan
    In this study, we investigate optical properties of metal nanoparticle crystals fabricated by implanting copper (Cu) ions into single silica (SiO2) crystals with 400 key at various ion doses. The Cu implanted SiO2 (SiO2:Cu) crystal produces a broadband luminescence emission, ranging from blue to yellow, and having a blue luminescence peak at 546 nm. Such anomalous luminescence emission bands suggest that the ion implantation may give rise to aggregation of Cu nanoparticles in the host matrix. The boundary element method-based modelling of a given Cu nanoparticle aggregation was employed to justify the broadband luminescence emission. Formation of Cu nanoparticles in SiO2 is predicted through their optical absorption data. The experimental results are compared with results of Mie calculations and we observe that the higher ion dose produces the larger particle size. (C) 2016 Elsevier Ltd. All rights reserved.
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    Experimental and numerical optical characterization of plasmonic copper nanoparticles embedded in ZnO fabricated by ion implantation and annealing
    (ELSEVIER SCIENCE SA, 2016) Le, Khai Q.; Nguyen, Hieu P. T.; Quang Minh Ngo; Canimoglu, Adil; Can, Nurdogan
    Here we describe the successfully fabrication of metal nanoparticle crystals by implanting copper (Cu) ions into single zinc oxide (ZnO) crystals with ion energy of 400 keV at ion doses of 1 x 10(16) to 1 x 10(17) ions/cm2. After implantation and post-annealing treatment, the Cu implanted ZnO produces a broad range of luminescence emissions, ranging from green to yellow. A green luminescence peak at 550 nm could be ascribed to the isolated Cu ions. The changes in luminescence emission bands between the initial implant and annealed suggest that the implants give rise to clustering Cu nanoparticles in the host matrix but that the annealing process dissociates these. Numerical modelling of the Cu nanoparticles was employed to simulate their optical properties including the extinction cross section, electron energy loss spectroscopy and cathodoluminescence. We demonstrate that the clustering of nanoparticles generates Fano resonances corresponding to the generation of multiple resonances, while the isolation of nanoparticles results in intensity amplification. (C) 2016 Elsevier B.V. All rights reserved.
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    Studies on luminescence from a cerium-doped strontium stannate phosphor
    (WILEY-BLACKWELL, 2015) Karabulut, Yuksel; Ayvacikli, Mehmet; Canimoglu, Adil; Garcia Guinea, Javier; Can, Nurdogan
    The crystal structure and morphology of Ce3+-doped SrSnO3 materials prepared using the solid-state reaction method were extensively characterized using experimental techniques. X-Ray diffraction results show that the cerium substitution of strontium does not change the structure of the strontium stannate. Raman spectroscopy was used to investigate the microstructures and lattice vibrations. Environmental scanning electron microscopy images showed that phosphors aggregate and their particles form irregular shapes. SrSnO3 exhibits an intense green emission with a broad band originating from the 5d(1)4f(1) transition of cerium. It was observed that, after exposure to beta-irradiation, the glow curve of this material has two broad thermoluminescence peaks, one centered at similar to 127 degrees C and the other at similar to 245 degrees C for a heating rate of 5 K/s. The kinetic parameters, which include the frequency factor and the activation energy of the material, were calculated using Chen's method, after beta-irradiation. The fading and reusability of the phosphor were also studied and it was found that the phosphor is suitable for radiation dosimetry. Copyright (c) 2014 John Wiley & Sons, Ltd.