• Transactions on Electrical and Electronic Materials
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• v.10 no.3
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• pp.89-92
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• 2009

High-quality Al-N doped p-type ZnO thin films were deposited on Si and buffer layer/Si by DC magnetron sputtering in a mixture of $N_2$ and $O_2$ gas. The target was ceramic ZnO mixed with $Al_2O_3$ (2 wt%). The p-type ZnO thin films showed a carrier concentration in the range of $1.5{\times}10^{15}{\sim}2.93{\times}10^{17}\;cm^{-3}$, resistivity in the range of 131.2${\sim}$2.864 ${\Omega}cm$, mobility in the range of 3.99${\sim}$31.6 $cm^2V^{-1}s^{-l}$, respectively. It was easier to dope p-type ZnO films on Si substrates than on buffer layer/Si. The film grown on Si showed the highest quality of photoluminescence (PL) characteristics. The Al donor energy level depth $(E_d)$ of Al-N codoped ZnO films was reduced to about 50 meV, and the N acceptor energy level depth $(E_a)$ was reduced to 63 meV.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.11
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• pp.969-973
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• 2009

In this study, the electrical and optical properties of $(SiO_2)_x(ZnO)_{100-x}$ (SZO) films prepared on the coming 7059 glass substrates by using rf-magnetron sputtering method are investigated. The deposition rate becomes maximum near 3 wt.% and gradually decreases when the $SiO_2$ content further increases. The growth rates of the SZO film with $SiO_2$ content of 3 wt.% is $4\;{\AA}/s$. We found that the average transmittance of all films is over 80% in the wavelength range above 500 nm. The optical band gap were decreased from 3.52 to 3.33 eV as an increase the deposition thickness. X-ray diffraction patterns showed that the film with a relatively low $SiO_2$ content (< 4 wt.%) is amorphous. SZO film with the $SiO_2$ contents of 2 wt.% showed the resistivity of about $3.8{\times}10^{-3}\;{\Omega}{\cdot}cm$. The sheet resistance decreases with increasing the heat treatment temperature.

• Corrosion Science and Technology
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• v.11 no.1
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• pp.1-8
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• 2012

The development of martensitic grades which can be processed in continuous galvanizing lines requires the reduction of the oxides formed on the steel during the hot dip process. This reduction mechanism was investigated in detail by means of High Resolution Transmission Electron Microscopy (HR-TEM) of cross-sectional samples. Annealing of a martensitic steel in a 10% $H_2+N_2$ atmosphere with the dew point of $-35^{\circ}C$ resulted in the formation of a thin $_{C-X}MnO.SiO_{2}$ (x>1) oxide film and amorphous $_{a-X}MnO.SiO_{2}$ oxide particles on the surface. During the hot dip galvanizing in Zn-0.13%Al, the thin $_{C-X}MnO.SiO_{2}$ (x>1) oxide film was reduced by the Al. The $_{a-X}MnO.SiO_{2}$ (x<0.9) and $a-SiO_{2}$ oxides however remained embedded in the Zn coating close to the steel/coating interface. No $Fe_{2}Al_{5-X}Zn_{X}$ inhibition layer formation was observed. During hot dip galvanizing in Zn-0.20%Al, the $_{C-X}MnO.SiO_{2}$ (x>1) oxide film was also reduced and the amorphous $_{a-X}MnO.SiO_{2}$ and $a-SiO_{2}$ particles were embedded in the $Fe_{2}Al_{5-X}Zn_{X}$ inhibition layer formed at the steel/coating interface during hot dipping. The results clearly show that Al in the liquid Zn bath can reduce the crystalline $_{C-X}MnO.SiO_{2}$ (x>1) oxides but not the amorphous $_{a-X}MnO.SiO_{2}$ (x<0.9) and $a-SiO_{2}$ oxides. These oxides remain embedded in the Zn layer or in the inhibition layer, making it possible to apply a Zn or Zn-alloy coating on martensitic steel by hot dipping. The hot dipping process was also found to deteriorate the mechanical properties, independently of the Zn bath composition.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.05c
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• pp.25-28
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• 2001

The objectives of this paper are to demonstrate the electrical degradation phenomena with Si atom's behaviors in the grainboundary of semiconducting ZnO ceramics. The ZnO ceramic devices used in this investigation were fabricated by standard ceramic techniques. Especially, $SiO_2$ were added to analyze the degradation characteristics with Si and sintered in oxygen ambient at $1300^{\circ}C$. The conditions of DC degradation test were $115{\pm}2^{\circ}C$ for 13h. Using XRD and SEM, the phase and microstructure of samples were analyzed respectively. E-J analysis was used to determine $\alpha$. Frequency analysis was accomplished to understand $R_g$ and $R_b$ at the equivalent circuit. Electrical stability improved as the amount of $SiO_2$ addition increased. This results were explain by the quantitative analysis and the line scanning method of EPMA.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.575-578
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• 2004

The charging tendency of $Zn_2SiO_4:Mn^{2+}$ phosphor surface was modified in order to improve discharging characteristic of green cell in an ac-plasma display panel (ac-PDP). The Zinc-silicate ($Zn_2SiO_4:Mn^{2+}$) green-emitting phosphor was coated with magnesium oxide(MgO), which is viable to have positive charge on the surface. After fabricating the green cell with MgO-coated $Zn_2SiO_4:Mn^{2+}$, the electrical and optical properties in the cell were examined. It was found that the dynamic voltage margin could be increased while the address time was reduced. It may be ascribed to the change of charging tendency of $Zn_2SiO_4:Mn^{2+}$ phosphor by MgO coating, which makes it possible to stable wall-charge accumulation. When $Zn_2SiO_4:Mn^{2+}$ phosphor was coated with 1.3wt%-MgO, the address time was reduced 1.2 ${\mu}s$ and the address voltage lowered 25 V without any misfiring problem, compared to those of typical $Zn_2SiO_4:Mn^{2+}$ phosphor layer. The luminescence intensity of green cell using MgO-coated phosphor layer was also improved by 10%.

• Journal of the Korean Ceramic Society
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• v.40 no.7
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• pp.637-643
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• 2003

In order to improve the photoluminescent properties and crystallinity, Zn$_2$SiO$_4$:Mn, M(M=Cr, Ti) phosphors were synthesized by the sol-gel method. The willemite single phase was obtained at 110$0^{\circ}C$, which is lower temperature than that of the conventional solid-state reaction (130$0^{\circ}C$). The characteristics of fired samples were obtained by a 147 nm excitation source under VUV (Vacuum Ultraviolet). To investigation the effect of co-dopant, the content of Mn and the ratio of $H_2O$ to TEOS was fixed as 2 ㏖% and 36. 1, respectively. The highest emission intensity was obtained when the concentration of Cr and Ti was 0.1 ㏖% relative to Zn$_2$SiO$_4$:Mn. While the emission intensity decrease continuously the decay time improved as increased the Cr concentration. In the case of Ti added samples, however, the emission intensity increase up to 2 ㏖％ concentration.

• Korean Journal of Optics and Photonics
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• v.3 no.4
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• pp.205-216
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• 1992

Distribution of electric fields of surface plasmons at resonance and off-resonance angles were calculated and compared. As applications of surface plasmon resonance, (1) optical constants of ZnS films overcoated on Ag films were measured as the thickness of ZnS films increased, (2) four surface plasmon resonances distributed spatially due to the different thickness of SiO thin films overcoated on Ag films were observed in a picture frame by employing diverging waves of incidence, and (3) patterns of SiO thin films such as a grating and a character "가" overcoated on Ag films were measured by employing collimated waves of incidence.

• Bulletin of the Korean Chemical Society
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• v.31 no.12
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• pp.3723-3729
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• 2010

We investigated the high-excitation voltage cathodoluminescence (CL) performance of blue light-emitting (ZnS:Ag,Al,Cl) and green light-emitting (ZnS:Cu,Al) phosphors coated with metal oxides ($SiO_2$, $Al_2O_3$, and MgO). Hydrolysis of the metal oxide precursors tetraethoxysilane, aluminum isopropoxide, and magnesium nitrate, with subsequent heat annealing at $400^{\circ}C$, produced $SiO_2$ nanoparticles, an $Al_2O_3$ thin film, and MgO scale-type film, respectively, on the surface of the phosphors. Effects of the phosphor surface coatings on CL intensities and aging behavior of the phosphors were assessed using an accelerating voltage of 12 kV. The MgO thick film coverage exhibited less reduction in initial CL intensity and was most effective in improving aging degradation. Phosphors treated with a low concentration of magnesium nitrate maintained their initial CL intensities without aging degradation for 2000 s. In contrast, the $SiO_2$ and the $Al_2O_3$ coverages were ineffective in improving aging degradation.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1356-1359
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• 2007

• Metals and materials international
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• v.24 no.6
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• pp.1241-1248
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• 2018

The reactive wetting behaviors of molten Zn-Al-Mg alloys on MnO- and amorphous (a-) $SiO_2$-covered steel sheets were investigated by the sessile drop method, as a function of the Al and Mg contents in the alloys. The sessile drop tests were carried out at $460^{\circ}C$ and the variation in the contact angles (${\theta}_c$) of alloys containing 0.2-2.5 wt% Al and 0-3.0 wt% Mg was monitored for 20 s. For all the alloys, the MnO-covered steel substrate exhibited reactive wetting whereas the $a-SiO_2$-covered steel exhibited nonreactive, nonwetting (${\theta}_c>90^{\circ}$) behavior. The MnO layer was rapidly removed by Al and Mg contained in the alloys. The wetting of the MnO-covered steel sheet significantly improved upon increasing the Mg content but decreased upon increasing the Al content, indicating that the surface tension of the alloy droplet is the main factor controlling its wettability. Although the reactions of Al and Mg in molten alloys with the $a-SiO_2$ layer were found to be sluggish, the wettability of Zn-Al-Mg alloys on the $a-SiO_2$ layer improved upon increasing the Al and Mg contents. These results suggest that the wetting of advanced high-strength steel sheets, the surface oxide layer of which consists of a mixture of MnO and $SiO_2$, with Zn-Al-Mg alloys could be most effectively improved by increasing the Mg content of the alloys.