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Sang-wook Han - One of the best experts on this subject based on the ideXlab platform.

  • Structural and electrical properties of Nitrogen-ion implanted ZnO nanorods
    Current Applied Physics, 2011
    Co-Authors: C.-h. Kwak, Y.-b. Lee, Seungwan Seo, Song-gang Kim, Chang-in Park, Bum-kyu Kim, D.w. Jeong, Jongwoon Kim, Zhenlan Jin, Sang-wook Han
    Abstract:

    Abstract This study examined the micro-structural and electrical properties of Nitrogen-ion implanted ZnO nanorods. Nitrogen Ions (N + s) with energy of 50 keV and beam flux of 10 16 particles/cm 2 were implanted on vertically-aligned ZnO nanorods. Energy dispersive X-ray spectroscopy measurements showed that N + s were spread uniformly over the nanorods. Extended X-ray absorption fine structure (EXAFS) measurements suggested that the implanted N + s had partially substituted for the oxygen sites. The I–V characteristic curves showed that the N + -implanted nanorods were n-type. Moreover, annealing at 800 °C enhanced the charge carrier density in the nanorods by 10-fold, compared to the N + -implanted and unannealed ZnO nanorods.

  • Structural and Optical Properties of Nitrogen-Ion-Implanted ZnO Nanorods
    Journal of the Korean Physical Society, 2008
    Co-Authors: S.-h. Park, Ye-ji Lee, C.-h. Kwak, S.-y. Seo, S.-h. Kim, Yong-dae Choi, Sang-wook Han
    Abstract:

    We present a study of the structural and the optical properties of Nitrogen-ion-implanted ZnO nanorods. Vertically-aligned ZnO nanorods were synthesized on Al2O3 substrates by using a catalyst-free metal-organic chemical vapor deposition (MOCVD) procedure. Nitrogen Ions with an energy of 120 keV and an ion ux of 1 1016 particles/cm2 were implanted on the verticallyaligned ZnO nanorods. The structural properties were studied by using various techniques, including eld emission transmission electron microscopy (FE-TEM), X-ray di raction (XRD), and X-ray absorption ne structure (XAFS) analyses. The XRD measurements revealed that the crystalline properties of the Nitrogen-ion-implanted ZnO nanorods were comparable with those of the as-grown ZnO nanorods. However, the XAFS analysis demonstrated that the bonding lengths of atomic pairs on the c-axis were slightly elongated and that the ion implantation caused an extra structural disorder of Zn-O pairs. The FE-TEM revealed that the nanorods had structurally-damaged spots along the entire length of the nanorods. From the photoluminescence (PL) spectra, we observed a considerably weak main donor-acceptor transition peak at 3.02 eV in the temperature range of 5 300 K. The blue shift and the intensity decrease of the main transition peak strongly suggest that the implanted Nitrogen Ions play a role in the optical property changes of the nanorods.

C.-h. Kwak - One of the best experts on this subject based on the ideXlab platform.

  • Structural and electrical properties of Nitrogen-ion implanted ZnO nanorods
    Current Applied Physics, 2011
    Co-Authors: C.-h. Kwak, Y.-b. Lee, Seungwan Seo, Song-gang Kim, Chang-in Park, Bum-kyu Kim, D.w. Jeong, Jongwoon Kim, Zhenlan Jin, Sang-wook Han
    Abstract:

    Abstract This study examined the micro-structural and electrical properties of Nitrogen-ion implanted ZnO nanorods. Nitrogen Ions (N + s) with energy of 50 keV and beam flux of 10 16 particles/cm 2 were implanted on vertically-aligned ZnO nanorods. Energy dispersive X-ray spectroscopy measurements showed that N + s were spread uniformly over the nanorods. Extended X-ray absorption fine structure (EXAFS) measurements suggested that the implanted N + s had partially substituted for the oxygen sites. The I–V characteristic curves showed that the N + -implanted nanorods were n-type. Moreover, annealing at 800 °C enhanced the charge carrier density in the nanorods by 10-fold, compared to the N + -implanted and unannealed ZnO nanorods.

  • Structural and Optical Properties of Nitrogen-Ion-Implanted ZnO Nanorods
    Journal of the Korean Physical Society, 2008
    Co-Authors: S.-h. Park, Ye-ji Lee, C.-h. Kwak, S.-y. Seo, S.-h. Kim, Yong-dae Choi, Sang-wook Han
    Abstract:

    We present a study of the structural and the optical properties of Nitrogen-ion-implanted ZnO nanorods. Vertically-aligned ZnO nanorods were synthesized on Al2O3 substrates by using a catalyst-free metal-organic chemical vapor deposition (MOCVD) procedure. Nitrogen Ions with an energy of 120 keV and an ion ux of 1 1016 particles/cm2 were implanted on the verticallyaligned ZnO nanorods. The structural properties were studied by using various techniques, including eld emission transmission electron microscopy (FE-TEM), X-ray di raction (XRD), and X-ray absorption ne structure (XAFS) analyses. The XRD measurements revealed that the crystalline properties of the Nitrogen-ion-implanted ZnO nanorods were comparable with those of the as-grown ZnO nanorods. However, the XAFS analysis demonstrated that the bonding lengths of atomic pairs on the c-axis were slightly elongated and that the ion implantation caused an extra structural disorder of Zn-O pairs. The FE-TEM revealed that the nanorods had structurally-damaged spots along the entire length of the nanorods. From the photoluminescence (PL) spectra, we observed a considerably weak main donor-acceptor transition peak at 3.02 eV in the temperature range of 5 300 K. The blue shift and the intensity decrease of the main transition peak strongly suggest that the implanted Nitrogen Ions play a role in the optical property changes of the nanorods.

Petros Abraha - One of the best experts on this subject based on the ideXlab platform.

  • the effect of plasma nitriding treatment time on the tribological properties of the aisi h13 tool steel
    Surface & Coatings Technology, 2019
    Co-Authors: Junji Miyamoto, Petros Abraha
    Abstract:

    Abstract In a conventional plasma nitriding mechanism and actual processing, the sample is primarily treated with Nitrogen Ions. Hence, nitriding is not mainly performed using neutral Nitrogen species, such as Nitrogen atoms. In this study, a novel method to control Nitrogen Ions was implemented, and nitriding of the AISI H13 tool steel was performed in electron-beam-excited plasma using neutral Nitrogen species and Nitrogen Ions. The effect of various treatment times on the formation of a hard but brittle compound layer were investigated, along with subsequent tribological change to the surface of the material. The results show that tool steel nitrided by neutral Nitrogen species for 6 h produced a diffusion-based nitrided layer (up to 60 μm) without altering the pretreatment surface finish (Ra = 14 nm), and there was a specific wear rate of less than one hundredth (4.3 × 10−7 mm3/N·m) compared with the untreated sample (2.9 × 10−5 mm3/N·m). Conversely, nitriding by Ions produced a rough, brittle compound layer on the surface of the tool steel. The samples with a compound layer exhibited a lower coefficient of friction than those with no compound layer.

P.d. Swift - One of the best experts on this subject based on the ideXlab platform.

  • A new type of TiN coating combining broad band visible transparency and solar control
    Renewable Energy, 2000
    Co-Authors: Geoffrey Smith, Avi Bendavid, P.d. Swift
    Abstract:

    Production of thin films of Titanium nitride (TiN) with N/Ti ratios as high as 1.3 has been achieved without destroying the metallic properties characteristic of stoichiometric TiN. The resultant change in mobile electron density shows that by depositing thin films the onset of a rise in reflection can be pushed out almost into the near infra red. It then becomes possible to produce films which transmit daylight neutrally at reasonably high levels, while still maintaining solar control in the NIR and a low emittance. Nitrogen ion assisted cathodic arc deposition has been used to achieve these results. Both the additional impacting and implanting Nitrogen Ions raise stoichiometry and help to reduce disorder so as to maintain good metallic character.

M. Vergnat - One of the best experts on this subject based on the ideXlab platform.

  • Visible photoluminescence in amorphous SiNx thin films prepared by reactive evaporation
    Applied Physics Letters, 2000
    Co-Authors: M. Molinari, H. Rinnert, M. Vergnat
    Abstract:

    Photoluminescence in the visible domain can be observed in amorphous silicon nitride (a-SiN x) alloys prepared by evaporation of silicon under a flow of Nitrogen Ions. A strong improvement of the photoluminescence intensity was obtained with annealing treatments in the range 500-1150 °C. Structural investigatIons were performed by infrared and Raman spectrometry experiments. The optical gap was obtained from transmission measurements in the ultraviolet, visible, and near infrared range. The evolutIons of the structure and the optical properties with annealing treatments are correlated to the evolution of the photoluminescence.