Idris KABALCI - Academia.edu (original) (raw)
Papers by Idris KABALCI
Nitrogen-doped TiO 2 thin films were prepared by pulsed laser deposition (PLD) by ablating metall... more Nitrogen-doped TiO 2 thin films were prepared by pulsed laser deposition (PLD) by ablating metallic Ti target with pulses of 248 nm wavelength in reactive atmospheres of O 2 /N 2 gas mixtures. The layers were characterized by UV-VIS spectrophotometry and variable angle spectroscopic ellipsometry with complementary profilometry for measuring the thickness of the films. Band gap and extinction coefficient values are presented for films deposited at different substrate temperatures and for varied N 2 content of the gas mixture. The shown tendencies are correlated to nitrogen incorporation into the TiO 2-x N x layers. It is shown that layers of significantly increased visible extinction coefficient with band gap energy as low as 2.89 eV can be obtained. A method is also presented how the spectroscopic ellipsometric data should be evaluated in order to result reliable band gap values. #
The (1−x)TeO2–xPbF2 binary glass system was investigated by differential thermal analysis (DTA) a... more The (1−x)TeO2–xPbF2 binary glass system was investigated by differential thermal analysis (DTA) and ultraviolet–visible-near-infrared
(UV–VIS-NIR) absorption spectrophotometer. Samples were prepared by melting the mixture of TeO2 and PbF2 in a platinum crucible at 800 ◦C
in air. Glass transition and the crystallization temperatures as function of the glass composition were measured by DTA.
An exothermic peak of crystallization temperature was observed at about 340±1 ◦C for all three samples. A second peak of peak crystallization
temperature was observed at about 400 ◦C for only the sample with 0.15 mol PbF2.
The mechanism and the activation energy for each crystallization peak were determined from the DTA curves measured with different heating
rates between 5 and 20 ◦C/min. The mechanism of the crystallization was found to be surface crystallization for the first exothermic peak for only
0.15 mol PbF2 sample; on the other hand, bulk crystallization was found for all samples. Corresponding activation energies are 814, 748, and
387 kJ/mol for the samples with 0.10, 0.15 and, 0.25 mol PbF2, respectively.
The mechanism and the activation energy for the second exothermic peak observed in the sample with 0.15 mol PbF2 were found to be bulk
crystallization and 415 kJ/mol, respectively.
The optical band gap, and Urbach energies were calculated from the absorption spectra measured between 300 and 800 nm at room temperature.
The optical bandgap varies from 2.02 to 1.90 eV when the PbF2 content increases from 0.10 to 0.25 mol in the glass matrix.
The microstructures of (1 − x)(TeO2)–xPbF2, (x = 0.1, 0.15, and 0.25mol) glasses were investigate... more The microstructures of (1 − x)(TeO2)–xPbF2, (x = 0.1, 0.15, and 0.25mol) glasses were investigated by using the Raman
spectroscopic technique. The effect of compositions on the TeO2 glass networks and the intensity ratios of the deconvoluted
Raman peaks were determined. The results confirm that the addition of modifiers to the glass network former shifts the Raman
intensity and the peak wavenumber values for each band in the 167–165, 652–645, and 747–755 cm−1 wavenumber regions.
The structural evaluation was recognized from the Raman spectra, with the structural units described as [TeO3+1] polyhedra,
[TeO3] trigonal pyramids, and [TeO4] trigonal bipyramids for this binary glass system. Heat-treatment of the samples shows
that themetastable crystalline phase of TeO2 known as γ -TeO2 is formed only when themodifier content is 10mol% in the glass
matrix. Transparent glass properties were not realized when the TeO2 amount was decreased to less than 10 mol% content.
Nitrogen-doped TiO2 thin films were prepared by pulsed laser deposition (PLD) by ablating metalli... more Nitrogen-doped TiO2 thin films were prepared by pulsed laser deposition (PLD) by ablating metallic Ti target with pulses of 248 nm wavelength
in reactive atmospheres of O2/N2 gas mixtures. The layers were characterized by UV–VIS spectrophotometry and variable angle spectroscopic
ellipsometry with complementary profilometry for measuring the thickness of the films. Band gap and extinction coefficient values are presented
for films deposited at different substrate temperatures and for varied N2 content of the gas mixture. The shown tendencies are correlated to nitrogen
incorporation into the TiO2–xNx layers. It is shown that layers of significantly increased visible extinction coefficient with band gap energy as low as
2.89 eV can be obtained. A method is also presented how the spectroscopic ellipsometric data should be evaluated in order to result reliable band
gap values.
X-ray diraction, infrared (IR), Raman spectroscopy and scanning electron microscope techniques h... more X-ray diraction, infrared (IR), Raman spectroscopy and scanning electron microscope techniques have beenused to investigate the microstructural properties of the glass materials. In this work, a new type of tellurite based
optical glasses with TeO2/Nb2O5/TiO2 for dierent xNb2O5 (x = 5, 10, 15, and 20 mol.%) glass compositions at
constant 5 mol.% TiO2 ratio were prepared. The eect of Nb2O5 contents on the structural unit of (95x)TeO2
(x)Nb2O55TiO2 glass network, and the intensity ratios of the Raman peaks were investigated. The results indicate
that for dierent Nb2O5 content 5 to 20 mol.% in the glass system, three vibrational peaks around 650, 800, and
920 cm1 which correspond to the structural bonding of the glass were observed in the range of 5002000 cm1
for the IR spectra. Furthermore, from the Raman results a structural evolution was determined with the number
of structural units such as [NbO6]7, TeO3+1 (polyhedra), TeO4 (trigonal bipyramids), TeO3 (trigonal pyramids)
or TeO3+1 (polyhedra), and [NbO4]3 for this ternary glass system.
ABSTRACT MxOy(M:Co, Mn, Nd)-doped SiO2 thin films were prepared by sol-gel method on glass substr... more ABSTRACT MxOy(M:Co, Mn, Nd)-doped SiO2 thin films were prepared by sol-gel method on glass substrates using Si(OC2H5)4 (tetraethylorthosilicate, TEOS,) as starting material. Si(OC2H5)4 was dissolved in ethanol and thus, precursor solution was prepared. Various layers of coatings were obtained at room temperature by sol-gel dip-coating process at a withdrawal speed of 10 cm/min. The coated substrates were exposed to heat treatment at 650° C. Structural and optical properties of the films were examined by UV-VIS (Lamda 2S Spectrophotometer), AFM (Atomic Force Microscopy) and SE (Spectroscopic Ellipsometry)
Physica Status Solidi (c), 2011
... Phys. Status Solidi C, 14 (2011) / DOI 10.1002/pssc.201084090 Optical properties and crystal... more ... Phys. Status Solidi C, 14 (2011) / DOI 10.1002/pssc.201084090 Optical properties and crystallization kinetics of (TeO2)(ZnO)(TiO2) glasses Idris Kabalci*, 1, Neşe Öztürk Körpe2, Tuğba Duran3, and Mustafa Özdemir3 ... Moreover, according to Sahar et al. ...
Journal of Raman Spectroscopy, 2009
The microstructures of (1 − x)(TeO 2 )-xPbF 2 , (x = 0.1, 0.15, and 0.25 mol) glasses were invest... more The microstructures of (1 − x)(TeO 2 )-xPbF 2 , (x = 0.1, 0.15, and 0.25 mol) glasses were investigated by using the Raman spectroscopic technique. The effect of compositions on the TeO 2 glass networks and the intensity ratios of the deconvoluted Raman peaks were determined. The results confirm that the addition of modifiers to the glass network former shifts the Raman intensity and the peak wavenumber values for each band in the 167-165, 652-645, and 747-755 cm −1 wavenumber regions. The structural evaluation was recognized from the Raman spectra, with the structural units described as [TeO 3+1 ] polyhedra, [TeO 3 ] trigonal pyramids, and [TeO 4 ] trigonal bipyramids for this binary glass system. Heat-treatment of the samples shows that the metastable crystalline phase of TeO 2 known as γ -TeO 2 is formed only when the modifier content is 10 mol% in the glass matrix. Transparent glass properties were not realized when the TeO 2 amount was decreased to less than 10 mol% content.
Physica Status Solidi (c), 2011
Journal of Luminescence, 2006
We investigated the near-infrared luminescence characteristics as a function of glass composition... more We investigated the near-infrared luminescence characteristics as a function of glass composition and Tm3+ ion concentration in a new type of Tm3+-doped tellurite glass: (1−x)TeO2–(x)PbF2. In the experiments, absorption measurements were first performed to determine the spontaneous emission probabilities and the radiative lifetimes for the 4f–4f transitions of the Tm3+ ions by using the Judd–Ofelt theory. Luminescence measurements show that
Tm3+-doped glasses have two emission bands that peak around 1470 nm and 1800 nm in the near infra... more Tm3+-doped glasses have two emission bands that peak around 1470 nm and 1800 nm in the near infrared, making them potentially important in the development of fiber-optic amplifiers and fiber lasers. The relative strength and the quantum efficiency of these bands depend on the glass composition as well as the active ion concentration. In this study, we have investigated the variation of the luminescence strengths as a function of glass composition and Tm3+ ion concentration in a new type of Tm3+-doped tellurite glass. In the experiments, two sets of samples with the host composition (1-x)TeO2-(x)PbF2 were prepared. In the first set, the active ion concentration was constant (1 mol. % Tm3+) and x=10, 15, 17, 20, 22 and 25 mol. %. The second set had samples with x=10 mol. % and the active ion concentration varied from 0.2 to 1 mol. %. In the experiments, absorption measurements were first made to determine the spontaneous emission probabilities of the 4f-4f transitions of the Tm3+ ions. The calculations were made by using the Judd-Ofelt theory. The samples were then excited with a 785-nm diode to measure the relative emission strengths of the 1470-nm and 1800-nm bands. Our results show that as the Tm3+ ion concentration increases from 0.2 mol. % to 1 mol. %, the ratio of the 1470-nm intensity decreases from 0.98 to 0.18 relative to that of the 1800-nm band.
Journal of Luminescence, 2006
We investigated the near-infrared luminescence characteristics as a function of glass composition... more We investigated the near-infrared luminescence characteristics as a function of glass composition and Tm3+ ion concentration in a new type of Tm3+-doped tellurite glass: (1−x)TeO2–(x)PbF2. In the experiments, absorption measurements were first performed to determine the spontaneous emission probabilities and the radiative lifetimes for the 4f–4f transitions of the Tm3+ ions by using the Judd–Ofelt theory. Luminescence measurements show that
We investigated the near-infrared luminescence characteristics as a function of glass composition... more We investigated the near-infrared luminescence characteristics as a function of glass composition and Tm 3+ ion concentration in a new type of Tm 3+ -doped tellurite glass: (1Àx)TeO 2 -(x)PbF 2 . In the experiments, absorption measurements were first performed to determine the spontaneous emission probabilities and the radiative lifetimes for the 4f-4f transitions of the Tm 3+ ions by using the Judd-Ofelt theory. Luminescence measurements show that with increasing thulium concentration, the strength of the 1470-nm band decreases with respect to that at 1800 nm due to cross relaxation. Emission cross sections were further determined as a function of host composition by using the luminescence data. For a fixed thulium concentration of 1 mol%, samples with x ¼ 20 mol% had the highest emission cross sections at 1470 and 1800 nm. Finally, lifetime measurements showed that the luminescence quantum efficiencies of the 1470-and 1800-nm transitions were maximum for host compositions with x ¼ 20 and 22 mol%, respectively.
Nitrogen-doped TiO 2 thin films were prepared by pulsed laser deposition (PLD) by ablating metall... more Nitrogen-doped TiO 2 thin films were prepared by pulsed laser deposition (PLD) by ablating metallic Ti target with pulses of 248 nm wavelength in reactive atmospheres of O 2 /N 2 gas mixtures. The layers were characterized by UV-VIS spectrophotometry and variable angle spectroscopic ellipsometry with complementary profilometry for measuring the thickness of the films. Band gap and extinction coefficient values are presented for films deposited at different substrate temperatures and for varied N 2 content of the gas mixture. The shown tendencies are correlated to nitrogen incorporation into the TiO 2-x N x layers. It is shown that layers of significantly increased visible extinction coefficient with band gap energy as low as 2.89 eV can be obtained. A method is also presented how the spectroscopic ellipsometric data should be evaluated in order to result reliable band gap values. #
The (1−x)TeO2–xPbF2 binary glass system was investigated by differential thermal analysis (DTA) a... more The (1−x)TeO2–xPbF2 binary glass system was investigated by differential thermal analysis (DTA) and ultraviolet–visible-near-infrared
(UV–VIS-NIR) absorption spectrophotometer. Samples were prepared by melting the mixture of TeO2 and PbF2 in a platinum crucible at 800 ◦C
in air. Glass transition and the crystallization temperatures as function of the glass composition were measured by DTA.
An exothermic peak of crystallization temperature was observed at about 340±1 ◦C for all three samples. A second peak of peak crystallization
temperature was observed at about 400 ◦C for only the sample with 0.15 mol PbF2.
The mechanism and the activation energy for each crystallization peak were determined from the DTA curves measured with different heating
rates between 5 and 20 ◦C/min. The mechanism of the crystallization was found to be surface crystallization for the first exothermic peak for only
0.15 mol PbF2 sample; on the other hand, bulk crystallization was found for all samples. Corresponding activation energies are 814, 748, and
387 kJ/mol for the samples with 0.10, 0.15 and, 0.25 mol PbF2, respectively.
The mechanism and the activation energy for the second exothermic peak observed in the sample with 0.15 mol PbF2 were found to be bulk
crystallization and 415 kJ/mol, respectively.
The optical band gap, and Urbach energies were calculated from the absorption spectra measured between 300 and 800 nm at room temperature.
The optical bandgap varies from 2.02 to 1.90 eV when the PbF2 content increases from 0.10 to 0.25 mol in the glass matrix.
The microstructures of (1 − x)(TeO2)–xPbF2, (x = 0.1, 0.15, and 0.25mol) glasses were investigate... more The microstructures of (1 − x)(TeO2)–xPbF2, (x = 0.1, 0.15, and 0.25mol) glasses were investigated by using the Raman
spectroscopic technique. The effect of compositions on the TeO2 glass networks and the intensity ratios of the deconvoluted
Raman peaks were determined. The results confirm that the addition of modifiers to the glass network former shifts the Raman
intensity and the peak wavenumber values for each band in the 167–165, 652–645, and 747–755 cm−1 wavenumber regions.
The structural evaluation was recognized from the Raman spectra, with the structural units described as [TeO3+1] polyhedra,
[TeO3] trigonal pyramids, and [TeO4] trigonal bipyramids for this binary glass system. Heat-treatment of the samples shows
that themetastable crystalline phase of TeO2 known as γ -TeO2 is formed only when themodifier content is 10mol% in the glass
matrix. Transparent glass properties were not realized when the TeO2 amount was decreased to less than 10 mol% content.
Nitrogen-doped TiO2 thin films were prepared by pulsed laser deposition (PLD) by ablating metalli... more Nitrogen-doped TiO2 thin films were prepared by pulsed laser deposition (PLD) by ablating metallic Ti target with pulses of 248 nm wavelength
in reactive atmospheres of O2/N2 gas mixtures. The layers were characterized by UV–VIS spectrophotometry and variable angle spectroscopic
ellipsometry with complementary profilometry for measuring the thickness of the films. Band gap and extinction coefficient values are presented
for films deposited at different substrate temperatures and for varied N2 content of the gas mixture. The shown tendencies are correlated to nitrogen
incorporation into the TiO2–xNx layers. It is shown that layers of significantly increased visible extinction coefficient with band gap energy as low as
2.89 eV can be obtained. A method is also presented how the spectroscopic ellipsometric data should be evaluated in order to result reliable band
gap values.
X-ray diraction, infrared (IR), Raman spectroscopy and scanning electron microscope techniques h... more X-ray diraction, infrared (IR), Raman spectroscopy and scanning electron microscope techniques have beenused to investigate the microstructural properties of the glass materials. In this work, a new type of tellurite based
optical glasses with TeO2/Nb2O5/TiO2 for dierent xNb2O5 (x = 5, 10, 15, and 20 mol.%) glass compositions at
constant 5 mol.% TiO2 ratio were prepared. The eect of Nb2O5 contents on the structural unit of (95x)TeO2
(x)Nb2O55TiO2 glass network, and the intensity ratios of the Raman peaks were investigated. The results indicate
that for dierent Nb2O5 content 5 to 20 mol.% in the glass system, three vibrational peaks around 650, 800, and
920 cm1 which correspond to the structural bonding of the glass were observed in the range of 5002000 cm1
for the IR spectra. Furthermore, from the Raman results a structural evolution was determined with the number
of structural units such as [NbO6]7, TeO3+1 (polyhedra), TeO4 (trigonal bipyramids), TeO3 (trigonal pyramids)
or TeO3+1 (polyhedra), and [NbO4]3 for this ternary glass system.
ABSTRACT MxOy(M:Co, Mn, Nd)-doped SiO2 thin films were prepared by sol-gel method on glass substr... more ABSTRACT MxOy(M:Co, Mn, Nd)-doped SiO2 thin films were prepared by sol-gel method on glass substrates using Si(OC2H5)4 (tetraethylorthosilicate, TEOS,) as starting material. Si(OC2H5)4 was dissolved in ethanol and thus, precursor solution was prepared. Various layers of coatings were obtained at room temperature by sol-gel dip-coating process at a withdrawal speed of 10 cm/min. The coated substrates were exposed to heat treatment at 650° C. Structural and optical properties of the films were examined by UV-VIS (Lamda 2S Spectrophotometer), AFM (Atomic Force Microscopy) and SE (Spectroscopic Ellipsometry)
Physica Status Solidi (c), 2011
... Phys. Status Solidi C, 14 (2011) / DOI 10.1002/pssc.201084090 Optical properties and crystal... more ... Phys. Status Solidi C, 14 (2011) / DOI 10.1002/pssc.201084090 Optical properties and crystallization kinetics of (TeO2)(ZnO)(TiO2) glasses Idris Kabalci*, 1, Neşe Öztürk Körpe2, Tuğba Duran3, and Mustafa Özdemir3 ... Moreover, according to Sahar et al. ...
Journal of Raman Spectroscopy, 2009
The microstructures of (1 − x)(TeO 2 )-xPbF 2 , (x = 0.1, 0.15, and 0.25 mol) glasses were invest... more The microstructures of (1 − x)(TeO 2 )-xPbF 2 , (x = 0.1, 0.15, and 0.25 mol) glasses were investigated by using the Raman spectroscopic technique. The effect of compositions on the TeO 2 glass networks and the intensity ratios of the deconvoluted Raman peaks were determined. The results confirm that the addition of modifiers to the glass network former shifts the Raman intensity and the peak wavenumber values for each band in the 167-165, 652-645, and 747-755 cm −1 wavenumber regions. The structural evaluation was recognized from the Raman spectra, with the structural units described as [TeO 3+1 ] polyhedra, [TeO 3 ] trigonal pyramids, and [TeO 4 ] trigonal bipyramids for this binary glass system. Heat-treatment of the samples shows that the metastable crystalline phase of TeO 2 known as γ -TeO 2 is formed only when the modifier content is 10 mol% in the glass matrix. Transparent glass properties were not realized when the TeO 2 amount was decreased to less than 10 mol% content.
Physica Status Solidi (c), 2011
Journal of Luminescence, 2006
We investigated the near-infrared luminescence characteristics as a function of glass composition... more We investigated the near-infrared luminescence characteristics as a function of glass composition and Tm3+ ion concentration in a new type of Tm3+-doped tellurite glass: (1−x)TeO2–(x)PbF2. In the experiments, absorption measurements were first performed to determine the spontaneous emission probabilities and the radiative lifetimes for the 4f–4f transitions of the Tm3+ ions by using the Judd–Ofelt theory. Luminescence measurements show that
Tm3+-doped glasses have two emission bands that peak around 1470 nm and 1800 nm in the near infra... more Tm3+-doped glasses have two emission bands that peak around 1470 nm and 1800 nm in the near infrared, making them potentially important in the development of fiber-optic amplifiers and fiber lasers. The relative strength and the quantum efficiency of these bands depend on the glass composition as well as the active ion concentration. In this study, we have investigated the variation of the luminescence strengths as a function of glass composition and Tm3+ ion concentration in a new type of Tm3+-doped tellurite glass. In the experiments, two sets of samples with the host composition (1-x)TeO2-(x)PbF2 were prepared. In the first set, the active ion concentration was constant (1 mol. % Tm3+) and x=10, 15, 17, 20, 22 and 25 mol. %. The second set had samples with x=10 mol. % and the active ion concentration varied from 0.2 to 1 mol. %. In the experiments, absorption measurements were first made to determine the spontaneous emission probabilities of the 4f-4f transitions of the Tm3+ ions. The calculations were made by using the Judd-Ofelt theory. The samples were then excited with a 785-nm diode to measure the relative emission strengths of the 1470-nm and 1800-nm bands. Our results show that as the Tm3+ ion concentration increases from 0.2 mol. % to 1 mol. %, the ratio of the 1470-nm intensity decreases from 0.98 to 0.18 relative to that of the 1800-nm band.
Journal of Luminescence, 2006
We investigated the near-infrared luminescence characteristics as a function of glass composition... more We investigated the near-infrared luminescence characteristics as a function of glass composition and Tm3+ ion concentration in a new type of Tm3+-doped tellurite glass: (1−x)TeO2–(x)PbF2. In the experiments, absorption measurements were first performed to determine the spontaneous emission probabilities and the radiative lifetimes for the 4f–4f transitions of the Tm3+ ions by using the Judd–Ofelt theory. Luminescence measurements show that
We investigated the near-infrared luminescence characteristics as a function of glass composition... more We investigated the near-infrared luminescence characteristics as a function of glass composition and Tm 3+ ion concentration in a new type of Tm 3+ -doped tellurite glass: (1Àx)TeO 2 -(x)PbF 2 . In the experiments, absorption measurements were first performed to determine the spontaneous emission probabilities and the radiative lifetimes for the 4f-4f transitions of the Tm 3+ ions by using the Judd-Ofelt theory. Luminescence measurements show that with increasing thulium concentration, the strength of the 1470-nm band decreases with respect to that at 1800 nm due to cross relaxation. Emission cross sections were further determined as a function of host composition by using the luminescence data. For a fixed thulium concentration of 1 mol%, samples with x ¼ 20 mol% had the highest emission cross sections at 1470 and 1800 nm. Finally, lifetime measurements showed that the luminescence quantum efficiencies of the 1470-and 1800-nm transitions were maximum for host compositions with x ¼ 20 and 22 mol%, respectively.