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  1. No Access

    Article

    Optical excitation study on the efficiency droop behaviors of InGaN/GaN multiple-quantum-well structures

    Efficiency droop is generally observed in electroluminescence under high current injection. Optical characterization on efficiency droop in InGaN/GaN multiple-quantum-well structures has been conducted at 12 K...

    Yuan** Sun, Hongying Guo, Lihua **, Yong-Hoon Cho, E.-K. Suh… in Applied Physics B (2014)

  2. No Access

    Article

    Apoptosis induced by copper oxide quantum dots in cultured C2C12 cells via caspase 3 and caspase 7: a study on cytotoxicity assessment

    We report herein the synthesis and characterization of copper oxide quantum dots and their cytotoxic impact on mouse C2C12 cells. The utilized CuO quantum dots were prepared by the one-pot wet chemical method ...

    Touseef Amna, Hoa Van Ba, M. Vaseem… in Applied Microbiology and Biotechnology (2013)

  3. No Access

    Article

    Inductively Coupled Plasma Etching of III-Nitrides in Cl2/Xe, Cl2/Ar AND Cl2/He

    The role of additive noble gases He, Ar and Xe to Cl2-based Inductively Coupled Plasmas for etching of GaN, AIN and InN were examined. The etch rates were a strong function of chlorine concentration, rf chuck pow...

    Hyun Cho, Y. B. Hahn, D. C. Hays, K. B. Jung… in MRS Online Proceedings Library (2011)

  4. No Access

    Article

    Nano structure formation in vacuum evaporated zinc phthalocyanine (ZnPc) thin films

    In this article we have reported the nano structure formation in ZincPhthalocyanine (ZnPc) thin films coated on glass substrates by thermal evaporation method. The structure of the films was analyzed by an X-r...

    S. Senthilarasu, Y. B. Hahn, Soo-Hyoung Lee in Journal of Materials Science: Materials in… (2008)

  5. No Access

    Article

    Evolution of ZnO nanostructures on silicon substrate by vapor-solid mechanism: Structural and optical properties

    ZnO nanostructures with different morphologies and sizes were synthesized on silicon substrate simply by the thermal evaporation of high-purity metallic zinc powder in the presence of oxygen without the use of...

    A. Umar, Y. H. Im, Y. B. Hahn in Journal of Electronic Materials (2006)

  6. No Access

    Article

    Inductively Coupled Plasma Etching in ICl- and IBr-Based Chemistries. Part I: GaAs, GaSb, and AlGaAs

    High-density plasma etching of GaAs, GaSb, and AlGaAs was performed inICl/Ar and IBr/Ar chemistries using an Inductively Coupled Plasma (ICP)source. GaSb and AlGaAs showed maxima in their etch rates for both p...

    Y. B. Hahn, D. C. Hays, H. Cho, K. B. Jung… in Plasma Chemistry and Plasma Processing (2000)

  7. No Access

    Article

    Inductively Coupled Plasma Etching in ICl- and IBr-Based Chemistries. Part II: InP, InSb, InGaP, and InGaAs

    A parametric study of Inductively Coupled Plasma (ICP) etching of InP, InSb, InGaP, and InGaAs has been carried out in ICl/Ar and IBr/Ar chemistries. Etch rates in excess of 3.1 for InP, 3.6 for InSb, 2.3 for ...

    Y. B. Hahn, D. C. Hays, H. Cho, K. B. Jung… in Plasma Chemistry and Plasma Processing (2000)

  8. No Access

    Article

    Selective Dry Etching of the GaN/InN/AlN, GaAs/AlGaAs and GaAs/InGaP Systems

    Selective etching of InN over GaN and AlN, and of GaAs over both AlGaAs and InGaP was examined with a number of different plasma chemistries under inductively coupled plasma conditions. Selectivities up to 55 ...

    D. C. Hays, C. R. Abernathy, W. S. Hobson, S. J. Pearton… in MRS Online Proceedings Library (1999)

  9. No Access

    Article

    Dry Etching to form Submicron Features in CMR Oxides: (Pr,Ba,Ca)MnO3 and (La,Sr)MnO3

    Effective pattern transfer into (Pr,Ba,Ca)MnO3 and (La,Sr)MnO3 has been achieved using Cl2/Ar discharges operated under Inductively Coupled Plasma conditions. Etch rates up to 900 Å-min−1 for (La,Sr)MnO3 and 300 ...

    K. P. Lee, K. B. Jung, H. Cho, D. Kumar… in MRS Online Proceedings Library (1999)

  10. Article

    Inductively Coupled Plasma Etching of III-Nitrides in Cl2/Xe, Cl2/Ar and Cl2/He

    The role of additive noble gases He, Ar and Xe to Cl2-based Inductively Coupled Plasmas for etching of GaN, AlN and InN were examined. The etch rates were a strong function of chlorine concentration, rf chuck pow...

    Hyun Cho, Y.B. Hahn, D.C. Hays, K.B. Jung… in MRS Internet Journal of Nitride Semiconduc… (1999)

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  11. No Access

    Article

    Plasma chemistries for high density plasma etching of SiC

    A variety of different plasma chemistries, including SF6, Cl2, ICl, and IBr, have been examined for dry etching of 6H-SiC in high ion density plasma tools (inductively coupled plasma and electron cyclotron resona...

    J. Hong, R. J. Shul, L. Zhang, L. F. Lester, H. Cho… in Journal of Electronic Materials (1999)

  12. No Access

    Article

    Mathematical modeling of the reduction process of iron ore particles in two stages of twin-fluidized beds connected in series

    A mathematical model is presented to describe the reduction process of iron ore particles in two stages of twin-fluidized beds (TFBs) connected in series: prereduction and final reduction stages. Main features...

    Y. B. Hahn, K. S. Chang in Metallurgical and Materials Transactions B (1998)

  13. No Access

    Article

    Wall-to-bed heat transfer in a circulating fluidized bed for the reduction of iron ore particles

    A model is presented that describes the wall-to-bed heat transfer in a circulating fluidized bed (CFB) used for the prereduction of iron ore in the smelting-reduction iron-making process. The model incorporate...

    Y. B. Hahn, Y. H. Im in Metallurgical and Materials Transactions B (1997)

  14. No Access

    Article

    Mathematical modeling of sulfide flash smelting process: Part II. Quantitative analysis of radiative heat transfer

    A mathematical model has been developed to describe the rate processes in an axisymmetric copper flash smelting furnace shaft. A particular feature of the model is the incorporation of the four-flux model to d...

    Y. B. Hahn, H. Y. Sohn in Metallurgical Transactions B (1990)

  15. No Access

    Article

    Mathematical modeling of sulfide flash smelting process: Part I. Model development and verification with laboratory and pilot plant measurements for chalcopyrite concentrate smelting

    A mathematical model has been developed to describe the various processes occurring in a flash furnace shaft. The model incorporates turbulent fluid dynamics, chemical reaction kinetics, and heat and mass tran...

    Y. B. Hahn, H. Y. Sohn in Metallurgical Transactions B (1990)

  16. No Access

    Article

    The trajectories and distribution of particles in a turbulent axisymmetric gas jet injected into a flash furnace shaft

    Numerical computations have been performed for the behavior of a vertical turbulent particle-laden gas jet exemplified by the shaft region of a flash-smelting furnace. The two-equation(k-ε) model was used to desc...

    Y. B. Hahn, H. Y. Sohn in Metallurgical Transactions B (1988)