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J.c. Pivin - One of the best experts on this subject based on the ideXlab platform.
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Ion irradiatIon studies of silver amorphous carbon nanocomposite thin film
Surface & Coatings Technology, 2013Co-Authors: R. Singhal, J.c. Pivin, R. Chandra, D.k. AvasthiAbstract:Abstract We study the optical and microstructural properties of silver/amorphous carbon (Ag/a-C) nanocomposite thin film and its modificatIon induced by swift heavy Ion irradiatIon. Ag nanoparticles (NPs) embedded in a-C matrix were synthesized by co-sputtering of Ag and graphite by 1.5 keV neutral Ar atom beam. These Ag NPs were irradiated by 120 MeV Ag Ions at different fluences ranging from 1 × 10 12 to 3 × 10 13 Ions/cm 2 . Optical absorptIon studies revealed that surface plasmon resonance of Ag NPs in pristine film occurs at a wavelength of ~ 430 nm and it shows a blue shift (~ 26 nm) with increasing Ion fluence up to 3 × 10 13 Ions/cm 2 . TransmissIon electron microscopy and Rutherford backscattering spectroscopy were used to quantify particle size and metal atomic fractIon, respectively, in the nanocomposite films. The growth of Ag NPs with bi-model distributIon at a fluence of 3 × 10 13 Ions/cm 2 was observed with Ion irradiatIon. Raman spectroscopy was used to investigate the effect of heavy Ion irradiatIon on carbon matrix. The blue shift in plasmonic wavelength is explained in terms of increase in sp 2 content in carbon matrix by heavy Ion irradiatIon due to thermal energy depositIon which leads to a decrease in dielectric properties of the matrix.
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Structural phase transformatIon in ZnS nanocrystalline thin films by swift heavy Ion irradiatIon
Solid State Communications, 2010Co-Authors: S. P. Patel, J.c. Pivin, D. Kanjilal, A. K. Chawla, R. Chandra, J. Prakash, P. K. Kulriya, L. KumarAbstract:Zinc sulfide (ZnS) thin films in zinc-blende (ZB) and wurtzite (W) phases have been fabricated by pulsed laser depositIon. 150 MeV Ni Ion beam irradiatIon has been carried out at different fluences ranging from 10(11) to 10(13) Ions/cm(2) at room temperature for Ion induced modificatIons. Structural phase transformatIon in ZnS from W to ZB phase is observed after high energy Ion irradiatIon which leads to the decrease in bandgap. GeneratIon of high pressure and temperature by thermal spike during MeV Ion irradiatIon along the Ion trajectory in the films is responsible for the structural phase transformatIon. (C) 2010 Elsevier Ltd. All rights reserved
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Electrical transport study of structural phase transitIons in C$_{60}$ films and the effect of swift heavy Ion irradiatIon
Solid State Communications, 2006Co-Authors: A. Kumar, D.k. Avasthi, F. Singh, R. Kumar, A. Tripathi, J.c. PivinAbstract:Three phase transitIons (face centered to simple cubic, surface rearrangement from (2×2) to (1×1) and glass transitIon) in fullerene thin films and the effect of 150 MeV Ti Ion irradiatIon on these transitIons have been studied, using temperature dependence of electrical resistivity measurements. The structural properties of the C60 thin films are studied by X-ray diffractIon, atomic force microscopy and UV–vis spectroscopy. It is observed that defect creatIon by Ion irradiatIon in the films lead to quenching and broadening of structural phase transitIons but the transitIon temperatures did not show significant shifting under Ion irradiatIon.
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Polymer conversIon into amorphous ceramics by Ion irradiatIon
Journal of Materials Science, 2002Co-Authors: Ernst Z. Kurmaev, Alexander Moewes, J.c. Pivin, M. Bach, K. Endo, Tomonori Ida, S. Shimada, Manfred Neumann, S. N. Shamin, David L. EdererAbstract:We present results of X-ray fluorescence measurements (carbon Kα and Si L2,3) of methylhydroxylsiloxane and phenylmethylhydroxylsiloxane films. The films are converted into amorphous ceramics by irradiatIon with 500 keV C and 3 MeV Au Ions. Changes in the compositIon (O/Si ratio) of some polysiloxane films are found when treated with Ion irradiatIon. It is shown that Ion irradiatIon induces a segregatIon of carbon atoms from methyl groups into diamond-like clusters whereas carbon atoms from phenyl groups maintain their sp2 configuratIon.
D.k. Avasthi - One of the best experts on this subject based on the ideXlab platform.
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engineering of electronic properties of single layer graphene by swift heavy Ion irradiatIon
Journal of Applied Physics, 2018Co-Authors: Sunil Kumar, Ashish Kumar, Ambuj Tripathi, Chetna Tyagi, D.k. AvasthiAbstract:In this work, swift heavy Ion irradiatIon induced effects on the electrical properties of single layer graphene are reported. The modulatIon in minimum conductivity point in graphene with in-situ electrical measurement during Ion irradiatIon was studied. It is found that the resistance of graphene layer decreases at lower fluences up to 3 × 1011 Ions/cm2, which is accompanied by the five-fold increase in electron and hole mobilities. The Ion irradiatIon induced increase in electron and hole mobilities at lower fluence up to 1 × 1011 Ions/cm2 is verified by separate Hall measurements on another irradiated graphene sample at the selected fluence. In contrast to the adverse effects of irradiatIon on the electrical properties of materials, we have found improvement in electrical mobility after irradiatIon. The increment in mobility is explained by considering the defect annealing in graphene after irradiatIon at a lower fluence regime. The modificatIon in carrier density after irradiatIon is also observed. Ba...
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Ion irradiatIon studies of silver amorphous carbon nanocomposite thin film
Surface & Coatings Technology, 2013Co-Authors: R. Singhal, J.c. Pivin, R. Chandra, D.k. AvasthiAbstract:Abstract We study the optical and microstructural properties of silver/amorphous carbon (Ag/a-C) nanocomposite thin film and its modificatIon induced by swift heavy Ion irradiatIon. Ag nanoparticles (NPs) embedded in a-C matrix were synthesized by co-sputtering of Ag and graphite by 1.5 keV neutral Ar atom beam. These Ag NPs were irradiated by 120 MeV Ag Ions at different fluences ranging from 1 × 10 12 to 3 × 10 13 Ions/cm 2 . Optical absorptIon studies revealed that surface plasmon resonance of Ag NPs in pristine film occurs at a wavelength of ~ 430 nm and it shows a blue shift (~ 26 nm) with increasing Ion fluence up to 3 × 10 13 Ions/cm 2 . TransmissIon electron microscopy and Rutherford backscattering spectroscopy were used to quantify particle size and metal atomic fractIon, respectively, in the nanocomposite films. The growth of Ag NPs with bi-model distributIon at a fluence of 3 × 10 13 Ions/cm 2 was observed with Ion irradiatIon. Raman spectroscopy was used to investigate the effect of heavy Ion irradiatIon on carbon matrix. The blue shift in plasmonic wavelength is explained in terms of increase in sp 2 content in carbon matrix by heavy Ion irradiatIon due to thermal energy depositIon which leads to a decrease in dielectric properties of the matrix.
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Electrical transport study of structural phase transitIons in C$_{60}$ films and the effect of swift heavy Ion irradiatIon
Solid State Communications, 2006Co-Authors: A. Kumar, D.k. Avasthi, F. Singh, R. Kumar, A. Tripathi, J.c. PivinAbstract:Three phase transitIons (face centered to simple cubic, surface rearrangement from (2×2) to (1×1) and glass transitIon) in fullerene thin films and the effect of 150 MeV Ti Ion irradiatIon on these transitIons have been studied, using temperature dependence of electrical resistivity measurements. The structural properties of the C60 thin films are studied by X-ray diffractIon, atomic force microscopy and UV–vis spectroscopy. It is observed that defect creatIon by Ion irradiatIon in the films lead to quenching and broadening of structural phase transitIons but the transitIon temperatures did not show significant shifting under Ion irradiatIon.
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Hydrogen loss under heavy Ion irradiatIon in polymers
Radiation Effects and Defects in Solids, 1999Co-Authors: V. K. Mittal, S. Lotha, D.k. AvasthiAbstract:Abstract The hydrogen loss behavior in polymers under heavy Ion irradiatIon is investigated for different electronic excitatIon energies. It is found that hydrogen loss under Ion irradiatIon depends on the electronic energy depositIon, and the type of bonds present in it. It is noticed that the hydrogen loss curve can be fitted with an equatIon contatining two exponential terms. The diminishing of hydrogen loss at higher fluences is discussed on the basis of overlapping of Ion tracks.
Hyung-jin Jung - One of the best experts on this subject based on the ideXlab platform.
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Ar + Ion irradiatIon in oxygen environment for improving wettability of polymethylmethacrylate
Journal of Materials Research, 1996Co-Authors: Seok-keun Koh, Won Kook Choi, Jun-sik Cho, Seok-kyun Song, Youngman Kim, Hyung-jin JungAbstract:Ion irradiatIon with various oxygen flow rates has been carried out to improve the wettability of polymethylmethacrylate (PMMA) to water and to enhance the adhesIon between Al and the polymer. Ar+ Ion and oxygen Ion were irradiated on the polymer, and amounts of Ions were changed from 5 × 1014 Ar+/cm2 to 5 × 1016 Ar+/cm2 by a broad Ion beam source. Oxygen gas from 0 ml/min to 7 ml/min was flowed near the polymer surface during the Ion irradiatIon, and the energy of Ions was changed from 500 eV to 1500 eV. The wetting angle was reduced from 68° to 49° with the Ar+ Ion irradiatIon only at 1 keV energy, to 43° with the oxygen Ion irradiatIon, and dropped to 8° with Ar+ Ion irradiatIon with flowing 4 ml/min oxygen gas near the polymer surface. Changes of wetting angle with oxygen gas and Ar+ Ion irradiatIon were explained by a two-step chemical reactIon among polymer matrix, energetic Ions, and oxygen gas. The effects of Ar+ Ion and oxygen Ion irradiatIon were explained by considering formatIon of hydrophilic groups due to a reactIon between irradiated polymer chain by energetic Ion irradiatIon and blown oxygen gas, and enhanced adhesIon between Al and PMMA was explained by the formatIon of electron acceptor groups in polymer and electron donors in metal, and by the chemical reactIon in the interface between irradiated polymer surface and deposited metal.
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Improving Wettability of PoIyMethylMetiiAcrylate by Ar+ Ion IrradiatIon in Oxygen Environment
MRS Proceedings, 1994Co-Authors: Seok-keun Koh, Won Kook Choi, Jun-sik Cho, Seok-kyun Song, Hyung-jin JungAbstract:Ion irradiatIon has been carried out to improve wettability of PMMA to water. The polymer was irradiated by argon and oxygen Ions, and amount of Ions was changed from 10 14 ArVcm 2 to 5xl0 16 Ar + /cm 2 . Ions energies were varied from 0.5 keV to 1.5 keV, and oxygen gas was flowed from 0 seem to 6 scan near the polymer surface during Ion irradiatIon. Wetting angle was reduced from 68 degree to 49 degree with increasing Ar + Ion irradiatIon, to 43 degree with Ch + Ion irradiatIon, and dropped to 8 degree with Ar + Ion irradiatIon with flowing 4 seem oxygen gas near the polymer surface. Recovery of wettability in dry air conditIon, and maintenance of it in dilute HC1 solutIon were explained in a view of formatIon of hydrophilic groups due to a reactIon between irradiated polymer chain by energetic Ion irradiatIon and flowing oxygen near the surface. ReactIons among polymer matrix, energetic Ions and oxygen gas to form hydrophilic group by energetic Ions were discussed in terms of a two-step reactIon, in which the first step is the creatIon of an unstable polymer chain by the Ion irradiatIon and the second step is a reactIon between the radicals and the oxygen gas.
L. Kumar - One of the best experts on this subject based on the ideXlab platform.
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Structural phase transformatIon in ZnS nanocrystalline thin films by swift heavy Ion irradiatIon
Solid State Communications, 2010Co-Authors: S. P. Patel, J.c. Pivin, D. Kanjilal, A. K. Chawla, R. Chandra, J. Prakash, P. K. Kulriya, L. KumarAbstract:Zinc sulfide (ZnS) thin films in zinc-blende (ZB) and wurtzite (W) phases have been fabricated by pulsed laser depositIon. 150 MeV Ni Ion beam irradiatIon has been carried out at different fluences ranging from 10(11) to 10(13) Ions/cm(2) at room temperature for Ion induced modificatIons. Structural phase transformatIon in ZnS from W to ZB phase is observed after high energy Ion irradiatIon which leads to the decrease in bandgap. GeneratIon of high pressure and temperature by thermal spike during MeV Ion irradiatIon along the Ion trajectory in the films is responsible for the structural phase transformatIon. (C) 2010 Elsevier Ltd. All rights reserved
Seok-keun Koh - One of the best experts on this subject based on the ideXlab platform.
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Ar + Ion irradiatIon in oxygen environment for improving wettability of polymethylmethacrylate
Journal of Materials Research, 1996Co-Authors: Seok-keun Koh, Won Kook Choi, Jun-sik Cho, Seok-kyun Song, Youngman Kim, Hyung-jin JungAbstract:Ion irradiatIon with various oxygen flow rates has been carried out to improve the wettability of polymethylmethacrylate (PMMA) to water and to enhance the adhesIon between Al and the polymer. Ar+ Ion and oxygen Ion were irradiated on the polymer, and amounts of Ions were changed from 5 × 1014 Ar+/cm2 to 5 × 1016 Ar+/cm2 by a broad Ion beam source. Oxygen gas from 0 ml/min to 7 ml/min was flowed near the polymer surface during the Ion irradiatIon, and the energy of Ions was changed from 500 eV to 1500 eV. The wetting angle was reduced from 68° to 49° with the Ar+ Ion irradiatIon only at 1 keV energy, to 43° with the oxygen Ion irradiatIon, and dropped to 8° with Ar+ Ion irradiatIon with flowing 4 ml/min oxygen gas near the polymer surface. Changes of wetting angle with oxygen gas and Ar+ Ion irradiatIon were explained by a two-step chemical reactIon among polymer matrix, energetic Ions, and oxygen gas. The effects of Ar+ Ion and oxygen Ion irradiatIon were explained by considering formatIon of hydrophilic groups due to a reactIon between irradiated polymer chain by energetic Ion irradiatIon and blown oxygen gas, and enhanced adhesIon between Al and PMMA was explained by the formatIon of electron acceptor groups in polymer and electron donors in metal, and by the chemical reactIon in the interface between irradiated polymer surface and deposited metal.
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Improving Wettability of PoIyMethylMetiiAcrylate by Ar+ Ion IrradiatIon in Oxygen Environment
MRS Proceedings, 1994Co-Authors: Seok-keun Koh, Won Kook Choi, Jun-sik Cho, Seok-kyun Song, Hyung-jin JungAbstract:Ion irradiatIon has been carried out to improve wettability of PMMA to water. The polymer was irradiated by argon and oxygen Ions, and amount of Ions was changed from 10 14 ArVcm 2 to 5xl0 16 Ar + /cm 2 . Ions energies were varied from 0.5 keV to 1.5 keV, and oxygen gas was flowed from 0 seem to 6 scan near the polymer surface during Ion irradiatIon. Wetting angle was reduced from 68 degree to 49 degree with increasing Ar + Ion irradiatIon, to 43 degree with Ch + Ion irradiatIon, and dropped to 8 degree with Ar + Ion irradiatIon with flowing 4 seem oxygen gas near the polymer surface. Recovery of wettability in dry air conditIon, and maintenance of it in dilute HC1 solutIon were explained in a view of formatIon of hydrophilic groups due to a reactIon between irradiated polymer chain by energetic Ion irradiatIon and flowing oxygen near the surface. ReactIons among polymer matrix, energetic Ions and oxygen gas to form hydrophilic group by energetic Ions were discussed in terms of a two-step reactIon, in which the first step is the creatIon of an unstable polymer chain by the Ion irradiatIon and the second step is a reactIon between the radicals and the oxygen gas.
