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Öğe Er3+ doped chalcogenide glasses and sputtered thin films: Structural and spectroscopic characterization(Institute of Electrical and Electronics Engineers Inc., 2016) Kabalci, I.; Hewak, D.W.In this research, we report Er3+ doped chalcogenide based glasses, well known for infrared transparency with various applications in the photonics and optoelectronics. Er3+ doped chalcogenide glasses were prepared by using vertical furnace with an argon gas atmosphere. For the structural and spectroscopic measurements, thin films at about 460nm thicknesses were deposited by using radio-frequency (RF) magnetron sputtering technique. Er3+ deposited thin films were annealed at different temperature as 450, 500, 550, and 600°C in the tube furnace and rapid thermal annealer (RTA) at 2°C/min, and 10°C/min heating rate, respectively. As a result, absorptions, luminescence, and structural properties of the Er3+ ion doped GLS thin films were affected from different annealing process. © 2016 IEEE.Öğe Hardness and structural properties of Yb3+ doped B2O3-ZnO-TiO2 glasses(Trans Tech Publications Ltd, 2017) Kabalci, I.In this study, the main thermal, structural and mechanical properties of optical glass materials were investigated by conventional glass melting method. The thermal properties of optical glass materials are important in that they constitute the first steps towards the investigation of other physical and chemical properties. According to the thermal properties of the material, the glass transition temperature, Tg, increases for different glass compositions. The XRD, XRF, FT-IR and hardness properties of the obtained optical glass materials were determined experimentally in terms of their structural and mechanical properties for their suitability for potential applications. XRD spectra obtained without heat treatment of glass materials show that the material structure is amorphous. In the same way, Vicker's hardness values of the glassware increase relative to the different glass compositions, resulting in a result that the material is influenced by the bonds between the constituents of the chemical components. © 2017 Trans Tech Publications, Switzerland.Öğe Investigation of Er doped zinc borate glasses by low-temperature photoluminescence(Elsevier Science Bv, 2017) Kostka, P.; Kabalci, I.; Tay, T.; Gladkov, P.; Zavadil, J.Er3+ doped (95-x)B2O3-xZnO-5TiO(2) (x = 45, 50 and 55 mol%) bulk glasses were prepared by conventional melt quenching method and investigated by transmission and photoluminescence (PL) spectroscopy. Transmission spectra exhibit sharp absorption bands at 364, 377, 406, 441, 448, 488, 521, 541, 651, 792, 974, and 1530 nm, that correspond to absorption on Er3+ ions and they are attributed to the optical transitions from the ground state I-4(15/2) to the excited states (4)G(9/2), (4)G(11/2), F-4(9/2), F-4(3/2), F-4(5/2), F-4(7/2), H-2(11/2), S-4(3/2), F-4(9/2), I-4(9/2), I-4(11/2) and I-4(3/2), respectively. The optical gap has been estimated around 3.5 eV with a tendency to increase with increasing ZnO content. Low-temperature PL properties of the Er3+ doped glasses and of the host glass itself were investigated. To achieve this goal, two different wavelengths (325 and 514.5 nm) were used for PL excitation. PL spectra excited by He-Cd laser at 325 nm were dominated by the host glass broad -band luminescence centred at around 570 nm. Simultaneously we observed narrow emission and absorption features due to 4f-4f electronic transitions in Er3+ ions superposed on the broad band host glass luminescence. We argue that these superposed narrow absorption dips represent a direct evidence of the energy transfer from the electronic structure of the host to 4f states of Er3+ ions. Fine structure of Er3+ emission bands at 980 and 1530 nm, corresponding to radiative transitions from the two lowest excited states of Er3+ ions to the ground state manifold have been investigated at room temperature and at 4 K, and a schematic energy diagram of Stark levels of I-4(11/2), I-4(13/2) and I-4(15/2) manifolds has been deduced.Öğe Thermal analysis and linear optical properties of (1-x)TeO2-(x)ZnCl2 optical glasses for photonic applications(Institute of Electrical and Electronics Engineers Inc., 2015) Kabalci, I.; Körpe, N.O.; Polat, R.The investigation covers the thermal and linear optical properties of binary TeO2-ZnCl2 optical glass systems contain different ZnCl2 compositions ranging from 10 to 40mol%. Preparation of the glass systems were realized by melting the mixture of TeO2 and ZnCl2 chemicals in a platinum crucible at 850°C for 60 min in air. In the experiments, thermal analysis was performed to determine the thermal characteristics such as, glass transition (Tg), crystallization (Tp), and melting (Tm) temperatures for different heating rates (B=10, 20, 30 and 40 °C/min) by using the differential thermal analysis (DTA) plot. By considering the DTA plots, the crystallization activation energies were determined by using the Ozawa and modified Kissinger equations. Finally, thermal analysis show that the crystallization activation energies were 487.6kJ/mol, 215.8kJ/mol, 392.kJ/mol, and 273.3kJ/mol for the x=10, 20, 30, and 40mol% ZnCl2 contents, respectively. Optical band gaps (direct and indirect) and Urbach energies of the glass samples were estimated from the absorption spectra measured between 300 and 800nm. The direct band gap energies decrease from 3.65 eV to 3.35 eV, and indirect band gap energies also decrease from 3.59 eV to 3.30 eV by increasing the ZnCl2 content from 10 to 40 mol%, respectively. © 2015 IEEE.
