Browsing by Author "Kibar, R"
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Item Effects of CdS quantum dot in polymer nanocomposites: In terms of luminescence, optic, and thermal resultsKeskin, IÇ; Türemis, M; Kati, MI; Kibar, R; Çetin, ACdS quantum dots (QDs) which have unique luminescence efficiency were synthesized by two-phase method using oleic acid (OA) as a surfactant. The nanocomposites have been obtained by blended CdS quantum dots with low-density polyethylene (LDPE) in different ratios. Primarily, radioluminescence (RL) properties were investigated as well as their structural (FT-IR, XRD), morphological (TEM, SEM), thermal (TG-DTA) and absorption (UV-Vis) properties of these nanocomposites. The RL peaks of OA-capped CdS QD were observed at 456 nm and 655 nm. As a consequence of the nanocomposites being doped with powder CdS QD, a significant blue shift was observed in the absorption bands. The optical band gap of CdS was calculated as- 2.3 eV. The nanocomposites blended with CdS QD, this value increased to- 2.7 eV. It has also been observed that nano particles cause nanocomposites to have lower melting temperatures.Item Radioluminescence Properties of Copper- and Terbium-Implanted Strontium TitanateArslanlar, YT; Kibar, R; Çetin, A; Canimoglu, AIn this study, the effects of Cu and Tb implantation on the radioluminescence (RL) properties of unimplanted and Cu- and Tb-implanted SrTiO3 (STO) crystals were investigated. The changes induced by heavy ion implants of the surface clearly modify the initial strong RL signals seen near 400750nm. During heating there are step increases in intensity at the RL spectrum near 60, 40, and 82K for unimplanted and Cu- and Tb-implanted samples, respectively.Item Luminescence characteristics and kinetic parameters of LiBaPO4: Tb3+, Dy3+phosphors synthesized by sol-gel methodKati, MI; Gökce, S; Keskin, IÇ; Türemis, M; Çetin, A; Kibar, RLiBaPO4: Tb3+, Dy3+ phosphors were prepared via sol-gel method by using the stoichiometric amounts of lithium nitrate LiNO3, barium nitrate Ba(NO3)2 and ammonium dihydrogen phosphate NH4H2PO4 as base materials. Morphology by scanning electron microscopy (SEM), structure by X-ray diffraction (XRD), thermal properties by Differential thermal analysis (DTA)/Thermogravimetric Analysis (TGA) and structural characteristics by Fourier transform infrared spectroscopy (FT-IR) were investigated. This paper presents luminescence properties using spectra from radioluminescence (RL), photoluminescence (PL), cathodoluminescence (CL) and, thermoluminescence (TL) and the influence of RE dopants (Tb3+, Dy3+) on the luminescent behavior of LiBaPO4. Computerized Glow Curve Deconvolution (CGCD) and Peak Shape Method were used to determine the kinetic parameters and the obtained results were evaluated. The RL results of un-doped LiBaPO4 showed the presence of a well-defined peak at 417 nm and a weaker band around 685 nm. Strong emissions were detected in the sample doped with Dy3+ correspond to 4F9/2 -> 6Hj transitions. Blue, yellow and red emissions were observed with transitions of 4F9/2 -> 6H15/2, 4F9/2 -> 6H13/2 and 4F9/2 -> 6H11/2, respectively. As for LiBaPO4: Tb3+, green emissions originated from the characteristic transitions (5D3 -> 7FJ (j = 6-3) and 5D4 -> 7FJ (j = 6-1)) of Tb+3 ion was seen. The RL, PL and CL spectra were identical, suggesting these green emissions. Dy3+ doped sample has three glow curves located at 72 degrees C, 145 degrees C and 204 degrees C, while the main temperature peak is measured at 240 degrees C for Tb3+ doped sample. Chromotographic studies of LiBa0 & sdot;98PO4: Dy3+0.02 reveals that calculated x and y color coordinates (0.3122, 0.3233) are very close to the white light.Item Comprehensive study on structural, thermal, morphological and luminescence (RL, PL, TL) properties of CaLa2(WO4)4: Tb3+, Dy3+ phosphors synthesized via sol-gel methodTüremis, M; Keskin, IÇ; Kati, MI; Çetin, A; Ay, K; Kibar, RTb3+/Dy3+ co-doped CaLa2(WO4)(4) (CLW: Tb3+/Dy3+) and its derivatives were synthesized by the sol-gel method. The morphology, thermal, structure and luminescent-optical properties the as-prepared light-emitting phosphors were characterized by utilizing scanning electron microscopy (SEM), differential thermal analysis (DTA)-thermogravimetric analysis (TG), X-ray diffraction (XRD) and radioluminescence (RL or X-ray luminescence) photoluminescence (PL) -thermoluminescence (TL or TSL) - optical absorption spectrometry. The Tb3+ and Dy3+ ions were singly or doubly doped and the results were examined in detail. Moreover, for these phosphors, the energy transfer mechanisms which depend on RL and PL spectra were determined. The samples excited by X-ray demonstrate characteristic luminescence peaks of Dy3+ (422, 480, 575, 663 and 747 nm) and Tb3+ (489, 544, 586, 620, 652 and 675 nm). These emissions are similar for RL and PL measurements. It could be said that the energy transfer efficiency of the host material is perfect for rare-earth ions. The synthesized phosphors exhibit various colors from yellow to blue under UV excitation. The optical band gaps of host CLW, CLW: Tb3(+), CLW: Dy3+ and co-doped CLW: Tb3+/Dy3+ were calculated at values 3.83 eV, 3.44 eV, 3.64 eV and 3.52 eV, respectively. From the results obtained, the CaLa2(WO4)(4): Tb3+, Dy(3+)phosphors may be one of the potential candidates for light-emitting diode.Item The radioluminescence and optical behaviour of nanocomposites with CdSeS quantum dotKeskin, IÇ; Türemis, M; Kati, MI; Kibar, R; Sirin, K; Çipiloglu, MA; Kus, M; Büyükcelebi, S; Çetin, AIn this work, highly luminescent alloyed CdSeS QDs are successfully synthesized by two phase route method by using oleic acid (OA) as a surfactant. OA capped CdSeS QDs prepared in two different synthesis duration were compared in terms of luminescence and optical properties. The nanocomposites blended with CdSeS QDs which have highly luminescent efficiency in different ratios by Low Density Polyethylene (LDPE) and these nanocomposites were mainly investigated radioluminescence (RL) and optical properties (UV/VIS absorption). Structural, morphological, thermal properties of the nanocrystal and nanocomposites were examined using; XRD, FT-IR, TEM, SEM, TG-DTA techniques. OA capped CdSeS and also nanocomposites were showed two RL spectrum peaks in green and red region at around 528 nm and 710 nm respectively. Also, it is seen that the radioluminescence intensity changes linearly with the particle size of the QDs and about 12% size change of quantum dot led to a threefold increase in RL intensity. The luminescence glow curves are in compliance with absorption and fluorescence spectra. The absorption bands showed a significant blue shift for the nanocomposites as compare to powder CdSeS. The optical band gap of the OA capped CdSeS calculated as 1.77 eV. It was observed that the optical band gap of LDPE was decreased by the adding ratio of CdSeS from 3.71 eV to 2.25 eV. (C) 2017 Elsevier B.V. All rights reserved.Item Third-order optical nonlinearities of Cu and Tb nanoparticles in SrTiO3Cetin, A; Kibar, R; Hatipoglu, M; Karabulut, Y; Can, NSome results of optical and nonlinear-optical properties of Cu and Tb nanoparticles implanted in SrTiO3 (STO) crystal are presented. The non-resonant third-order optical nonlinearities have been investigated by degenerate four wave mixing (DFWM), pump-probe and Z-scan techniques using femtosecond laser pulses. (C) 2010 Elsevier B.V. All rights reserved.Item Electrical and optical properties of chalcedony and striped chalcedonyÇetin, A; Okutan, M; Içelli, O; Yalçin, Z; San, SE; Kibar, R; Pesen, EThe electrical and optical properties of chalcedony (SiO2) and striped chalcedony are determined by the impedance and optical absorption spectroscopy techniques. The capacitance, impedance, dissipation factor and the complex dielectric constants are measured by the parallel plate technique in the voltage frequency range 100 to 10 MHz. The dissipation factor is measured as 1.2 and 0.7 for chalcedony and striped chalcedony respectively around 10 kHz. It is found that the striped chalcedony has a major complex broad band with two absorption bands that are centered at 225 and 275 nm. The chalcedony however, has a minor absorption band which is centered at 210 nm. (C) 2013 Elsevier Ltd. All rights reserved.Item Spectral, electron microscopic and chemical investigations of gamma-induced purple color zonings in amethyst crystals from the Dursunbey-Balikesir region of TurkeyHatipoglu, M; Kibar, R; Çetin, A; Can, N; Helvaci, C; Derin, HAmethyst crystals on matrix specimens from the Dursunbey-Balikesir region in Turkey have five representative purple color zonings: dark purple, light purple, lilac, orchid, and violet. The purple color zonings have been analyzed with optical absorption spectra in the visible wavelength region, chemical full trace element analyses (inductively coupled plasma-atomic emission spectroscopy and inductively coupled plasma-mass spectroscopy), and scanning electron microscopic images with high magnification. It can be proposed that the production of the purple color in amethyst crystals is due to three dominant absorption bands centered at 375, 530, and 675 nm, respectively. In addition, the purple color zonings are also due to four minor absorption bands centered at 435, 480, 620, and 760 nm. X-ray diffraction graphics of the investigated amethyst crystals indicate that these crystals are composed of a nearly pure alpha-quartz phase and do not include any moganite silica phase and/or other mineral implications. Trace element analyses of the amethyst crystals show five representative purple color zonings, suggesting that the absorption bands can be mainly attributed to extrinsic defects (chemical impurities). However, another important factor that influences all structural defects in amethyst is likely to be the gamma irradiation that exists during amethyst crystallization and its inclusion in host materials. This gamma irradiation originates from the large underlying intrusive granitoid body in the region of amethyst formation. Irradiation modifies the valence values of the impurity elements in the amethyst crystals. It is observed that the violet-colored amethyst crystals have the most stable and the least reversible coloration when exposed to strong light sources. This situation can be related to the higher impurity content of Fe (2.50 ppm), Co (3.1 ppm), Ni (38 ppm), Cu (17.9 ppm), Zn (10 ppm), Zr (3.9 ppm), and Mo (21.8 ppm).Item Radioluminescence and thermoluminescence of albite at low temperatureCan, N; Garcia-Guinea, J; Kibar, R; Çetin, A; Ayvacikli, M; Townsend, PDFeldspar as an archaeological and geological natural material for dating and retrospective dosimetry is receiving more and more attention because of its useful luminescence properties. In this study, the 25-280 K thermoluminescence (TL) and radioluminescence (RL) spectra in albite, which is a component of the two main feldspar series, the alkali feldspar (Na, K)AlSi(3)O(8) and the plagioclases (NaAlSi(3)O(8)-CaAl(2)Si(2)O(8)) have been presented for aliquots along (001) and (010) crystallographic orientations. There are four main emission bands that are considered to arise from complexes of intrinsic defects linked in larger complexes with impurities such as Na(+), Mn(2+) or Fe(3+) ions. The consequence of their association is to produce different luminescence efficiencies that produce wavelength sensitive TL curves. Radioluminescence data at low temperature for albites is distorted by contributions from the TL sites, even when the RL is run in a cooling cycle. This indicates the potential for a far more general problem for analysis of low temperature RL in insulating materials. (C) 2011 Elsevier Ltd. All rights reserved.Item X-ray irradiated thermo- and radioluminescence, structural and thermal characterization of septarian (powder&bulk) from MadagascarKeskin, IÇ; Kati, MI; Türemis, M; Gültekin, S; Üstün, S; Çetin, A; Kibar, RThe luminescence properties of septarian have been investigated for the first time in this study, which has been the subject of many studies in both geological and geophysical fields. This sediment with a calcium carbonate structure exhibited high luminescence properties with X-ray excitation. The radioluminescence (RL) and thermoluminescence (TL) properties were investigated as well as their structural (FT-IR, XRD), morphological (SEM), thermal (TG-DTA) and absorption (UV-Vis-NIR) properties of this sediment. The broad RL peak of septarian was observed at 640 nm. There was a significant increase in the RL intensities of the sifted samples compared with the bulk sample. The TL glow curves of septarian irradiated with X-rays exhibited intense main TL glow peak having the maximum temperatures at 116 degrees C and about 390 degrees C with a heating rate of 2 degrees C/s. Also; the TL kinetic parameters were reported; activation energy (E), frequency factor (s) and the order of kinetics (b) of the first peak have been determined in detail by using peak shape (PS) and Computerized Glow Curve Deconvolution (CGCD) methods. SEM and EDS analysis were performed for the two different layers of septarian. The light colored side with the amorphous structure of the sample has more impurities (such as Fe, Al, Zr, K) than the crystallized and darker side.Item Thermal properties of gem-quality moganite-rich blue chalcedonyHatipoglu, M; Tuncer, Y; Kibar, R; Çetin, A; Karali, T; Can, NIn this study, thermal properties and thermal decompositions of dehydration behaviour of gem-quality translucent blue chalcedonies, without banding or crystalline centre structure, from the Sancakaya-Eskisehir region in Turkey were studied by means of X-ray diffraction (XRD), inductively coupled plasma-atomic emission spectrometry (ICP-AES), Fourier transform infrared (FT-IR), thermoluminescence (TL), and simultaneously two thermal analyses of (DTA/TGA) spectroscopy. X-ray diffraction patterns of the blue chalcedony indicate the presence of two important chalcedonic silica phases with overlapped peaks at 4.26, 3.34, 2.28, 2.13, 1.82, 1.54, 1.38, and 137 A. During heating from the room temperature to 300 degrees C, the thermoluminescence pattern of the blue chalcedony shows a characteristic peak at 210 degrees C. This peak may be due to unusually high traces of the impurities S. Th, TI, U, and W. During heating from the room temperature to 1400 degrees C, the TGA pattern of the blue chalcedony indicates that the weight loss is due to the silanol water loss only, and that this loss occurs in a wide temperature range between about 170 and 954 degrees C. In addition, after making some corrections concerning the artefact mass gain, being due to the drift with buoyancy effect of the atmosphere in its TGA curve, the moganite-rich blue chalcedony shows a relatively lower mass loss of 0.202%. The DTA pattern of the blue chalcedony displays both endothermic and exothermic behaviours because of silica phase transformations. There are one distinctive sharp endotherm and three weaker endotherms at 806 degrees C. In addition, there is one distinctive sharp exotherm and one weaker exotherm at 1270 degrees C. (C) 2010 Elsevier B.V. All rights reserved.Item Optimizing Optical and Structural Properties of Nanocomposites by ZnO and BP-3Türemis, M; Keskin, IÇ; Kati, MI; Kibar, R; Sirin, K; Çanli, M; Çorumlu, V; Çetin, AThis study aims to find out usage of zinc oxide (ZnO) and 2-hydroxy-4-methoxybenzophenone (BP-3) for getting better optical and structural properties of nanocomposites. Polymer nanocomposites were prepared by adding zinc oxide for minimizing UV rays effects of the sun with the particle size of nanometer in different ratios to a low density polyethylene (LDPE). The polymer mixtures were synthesized by mixing nanocomposite samples with BP-3 featuring UV stabilizer. Besides making tensile testing measurements, in order to find out the optical, structural, mechanical and thermal changes, the new polymer nanocomposites were characterized by XRD, TG-DTA spectra, and SEM images. The samples with zinc oxide which show luminescent properties were examined in terms of radioluminescence features. Radioluminescence spectrum showed characteristic peaks of zinc oxide dispersed nanocomposites prepared with LDPE. The intensity of the characteristic peaks at 530 and 390 nm (exciton) increased by increasing rates of nanopowder zinc oxide while adding BP-3 to the composites caused a decrease in intensity of radioluminescence.Item Amethyst and morion quartz gemstone raw materials from Turkey: color saturation and enhancement by gamma, neutron and beta irradiationHatipoglu, M; Helvaci, C; Kibar, R; Çetin, A; Tuncer, Y; Can, NColor-enhancement investigations without using heating treatment from dull or pale to ideal saturation and/or changes to the formation of the rarer attractive colors are widely conducted to revalue abandoned gem material sources in the world. Such an investigation is carried out on pale or dull purple-colored amethyst and smoky-colored morion samples, which are two important gem species of the crystalline quartz (SiO2) mineral that are currently abandoned in natural deposits in Turkey because of their unattractive coloration. The results of color enhancements observed on these samples, after irradiation with artificial gamma, neutron and beta beams, were examined by comparing with samples with the ideal color saturation and also with colorless samples, using optical absorption (OA) and radioluminescence (RL) spectroscopy. The ICP-AES analyses reveal that the main impurity elements of over 100ppm in abundance in these quartz species are aluminum, iron and titanium for amethyst, and aluminum, iron, titanium and manganese for morion. The OA spectra indicate that vivid purple coloration of amethyst is due to the transmittance at about 395-420nm band gap as a result of absorbance peaks at 375, 480 and 530nm. These absorbances may be related to the unusual oxidized small proportions of certain impurity ions, after being exposed mainly to gamma irradiation, such as Al(IV) from the total aluminum, Ti(V) from the total titanium and Fe(IV) from the total iron, respectively. However, the RL spectroscopy of amethyst samples before and after they were exposed to artificial gamma, neutron and beta radiation beams demonstrates that the ions most affected by irradiation are Fe(IV) first and Al(IV) and Ti(V) second, and these ions represent the RL peaks at 600, 720 and 495nm, respectively. The OA spectra indicate that dark smoky coloration in morion is due to a lack of transmittance at the visible region as a result of the absorbance peaks at 375, 450-490, 620 and 730nm. These absorbances also may be related to the unusual oxidized small proportions of certain impurity ions by irradiation, such as Al(IV) from the total aluminum, Ti(V) from the total titanium and Mn(III) from the total manganese, respectively. In addition, the buoyancies of these absorbance peaks in the visible region produce the color hues between light smoky and dark smoky colorations in morion samples. These oxidized ion states are more resistant and stable against environmental destructive conditions in comparison with amethyst. Thus, the dark smoky coloration of morion becomes dull or pale after relatively longer periods. But, the RL spectroscopy of morion before and after being exposed to gamma, neutron and beta irradiation beams demonstrates that the most induced ions from the irradiation are Mn(III) and Al(IV) first and Ti(V) second. These ions represent the RL peaks at about 400, 720 and about 500nm, respectively.Item Luminescence behavior and Raman characterization of jade from TurkeyArslanlar, YT; Garcia-Guinea, J; Kibar, R; Çetin, A; Ayvacikli, M; Can, NResults are presented for the cathodoluminescence (CL), radioluminescence (RL) and thermoluminescence (TL) of jade from Turkey. Jade samples show broad band luminescence from green to red, which, using lifetime-resolved CL, reveals seven overlapping emissions, of which two are dominant. Green emission obtained using spatially resolved CL was associated with Mn2+ and emission bands centered near at 480 and 530 nm were attributed to P-3(0)-H-3(4) and D-1(2)-H-3(4) transitions of Pr3+, respectively. Different shifts of the peak-wavelengths for 326 and 565 nm were observed with varying jade compositions. The incorporation of the larger K ion causes non-linear variations of the cell dimensions and therefore changes in the Fe-O band distance. We suggest that stress of the jade structure can be linked to the luminescence emission at 326 nm. Raman spectra have also been recorded in order to provide an unequivocal identification of the type of jade. The mechanism for the luminescence of the jade is considered. (C) 2011 Elsevier Ltd. All rights reserved.Item Absorption and cathodoluminescence properties of Cu implanted SrTiO3Kibar, R; Cetin, A; Selvi, S; Can, NSingle crystal of SrTiO3 (STO) has been implanted at room temperature with 200 and 400 keV Cu ions to doses ranging from 1 x 10(16) to 1 x 10(17) ions/cm(2). The temperature cathodoluminescence (CL) of Cu implanted SrTiO3 has been studied in order to clarify the role of them in luminescence. Therefore CL measurements made on SrTiO3 implanted with metal ions are reported at 300 K with different excitation modulation frequencies. Room temperature ion implantation into surface layer changes low temperature CL signals both in terms of their relative intensities and also modifying the emission spectra. For such a large ion dose the unusual aspect is that the signals are still recognisable. The details of such changes and modifications of emission spectra are reported and discussed. A particularly important result is that the CL demonstrates that the implants cause bulk relaxations of the material that are apparent via the rear face CL. (C) 2009 Elsevier B.V. All rights reserved.Item Luminescence behaviour and Raman characterization of dendritic agate in the Dereyalak village (Eskisehir), TurkeyParali, L; Guinea, JG; Kibar, R; Cetin, A; Can, NResults are presented for the cathodoluminescence (CL), X-ray diffraction (XRD), inductively coupled plasma-atomic emission spectrometry (ICP-AES) and simultaneously two thermal analyses of (DTA/TGA) spectroscopy of dendritic agate which occurs in the Pliocene polymictic conglomerates of the Hoyuklu Formation, North West of the Dereyalak village (Eskisehir, Turkey). Micro-Raman measurements were performed on dendritic agate and then strong quartz and moganite peaks were identified at 465 and 501 cm(-1), respectively. Thermal analysis shows the loss of water and hydroxyl units occurs in 2 distinct stages: at 796 and 808 degrees C. Spatially resolved CL results at room temperature were recorded for chosen 3 different areas. Grey area (100% SiO2) displays the lowest CL emission. Brown area (99.7% SiO2 and 0.3% Fe2O3) contains exsolved non-detected ironed phases such as goethite-lepidochrocite to explain the brown colour and the iron point substitutional defects attributed to the 643 nm CL emission. White outer (98.7% SiO2 and 1.3% Al2O3) would be strongly disordered as observed in the amorphous Raman spectrum containing as inferred from the spectrum CL on the outer areas, particularly non-bridging oxygen hole centres (NBOHC) (317 nm) and [AlO4]degrees/H+ (380 nm) centres produced by large amounts of aluminium in the lattice (1.33% Al2O3). When it comes to collect the data in the time resolved CL spectrum, at least three broad emission bands were detected in: a green band of low intensity at about 496 nm, intense orange band at about 600 nm, and a red band at 670 nm. The CL emission at 670 rim shows some relationships between the hydroxyl or alkali content and the abundance of O-2 (super 3-) centres and E'(1) centres. Another conspicuous observed feature in the CL spectra of agates is the existence of an orange emission band centred at around 600 nm. The predominance of the yellow CL emission band and the high concentration of E'(1) centres are typical for agates formed by acidic volcanism processes. (C) 2011 Elsevier B.V. All rights reserved.Item Detailed luminescence (RL, PL, CL, TL) behaviors of Tb 3+and Dy 3+doped LiMgPO4 synthesized by sol-gel methodKeskin, IÇ; Türemis, M; Kati, MI; Gültekin, S; Arslanlar, YT; Çetin, A; Kibar, RItem Luminescence Behavior and Raman Characterization of Rhodonite from TurkeyCan, N; Guinea, JJG; Kibar, R; Cetin, ACathodoluminescence (CL) and optical absorption properties of rhodonite natural silicate mineral were investigated. CL spectra show an intense Mn2+ luminescence band, which occurs as broad-band emission in the orange-to-red range. The broadness of the emission is explained by strong interaction of 3d ions with the surrounding crystal field, which is strongly affected by lattice and atomistic vibrations of the ligands. Rhodonite rock exhibits luminescence maxima at 310, 425, and 626 nm. The Raman spectrum of rhodonite (from Turkey) is characterized by an intense band at about 668 cm(-1) assigned to nu(4) bending mode and showed additional bands exhibiting loss of degeneracy of the SiO4 units. A strong band at 408 cm(-1) is attributed to the nu(2) bending bond.Item Luminescence behaviour of beryl (aquamarine variety) from TurkeyKati, MI; Türemis, M; Keskin, IC; Tastekin, B; Kibar, R; Çetin, A; Can, NNatural blue-green beryl from Turkey has been investigated using scanning electron microscopy-energy-dispersive spectroscopy (SEM-EDS), X-ray diffraction (XRD) and Cathodoluminescence (CL). Beryl has the chemical formula Be3Al2Si6O18 and is hexagonal with space group P6/mcc. Chemical analyses of the beryl sample utilised inductively coupled plasma-atomic emission spectroscopy (ICP-AES) for major oxides and trace elements. It shows that the beryl sample is rich in Cs (531 ppm) and contains low concentrations of transition-metal ions, in total 2.29 wt.% Fe, 269 ppm Mn, V < 5 ppm and Cr 20 ppm. Ideas on the origin of the green colour of this mineral are presented. The CL spectrum of the bulk sample display intense broad band emission from similar to 360 to similar to 800 nm. (C) 2012 Elsevier B.V. All rights reserved.Item Effect of thermal treatment on linear optical properties of Cu nanoclustersKibar, R; Cetin, A; Can, NSilica glass was implanted with 50keV Cu+ ions at various fluences from 6 x 10(15) to 8 x 10(16) ions/cm(2) and thermally-annealed in air between room temperature to 1200 degrees C. UV/visible spectroscopy measurements reveal absorption bands at characteristics surface plasmon resonance (SPR) frequencies, signifying the formation of copper colloids in silica, even without thermal treatments. Such copper nanoclusters can be attributed to the relatively high mobility of copper atoms, even at ambient conditions. Using the equation derived from the framework of free-electron theory, the average radii of the Cu particles were found to be in the range 2-4 nm from the experimental surface plasmon absorption peaks. Radioluminescence (RL) spectra exhibited broad bands at 410 and 530 nm, associated with the presence of Cu+ ions in the as-implanted samples. The effect of thermal annealing in air on absorption and emission spectra of these Cu-implanted samples, as well as the formation of copper nanoclusters from original Cu+ ions, is discussed. (C) 2008 Elsevier B.V. All rights reserved.