• Proceedings of the IEEK Conference
• /
• 2007.07a
• /
• pp.441-442
• /
• 2007

We deposited nickel oxide(NiO) thin films on silicon(Si) substrates at Room temperature and $500^{\circ}C$ using a nickel target by reactive DC and RF sputtering. In addition, we anneal to NiO thin films deposited at room temperature. Using spectroscopic eillipsometry, we obtained optical characteristics of every films. We discussed relations of the optical and structural properties of NiO thin films with the oxygen flow rate, substrate temperature and annealing temperatures. Refraction was decreased and defect was increased when NiO thin films was annealed. We also analyzed the electrical characteristics of NiO films which deposited DC and RF sputtering method.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1999.11a
• /
• pp.429-432
• /
• 1999

The growth of $\textrm{YMnO}_3$ films directly on Si(100) substrates by RF magnetron sputtering system has been performed. The structural properties of $\textrm{YMnO}_3$ films on Si(100) by rapid thermal annealing(RTA) analysed by XRD(X-ray diffraction). The c-axis oriented $\textrm{YMnO}_3$ peaks were observed deposited in $\textrm{YMnO}_3$/Si(100) structure at RF power of 100W and at a temperature range of $840^{\circ}C$~$870^{\circ}C$ in oxygen ambient.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2000.11a
• /
• pp.157-161
• /
• 2000

Blue phosphor of Ba-Mg-Al-O:Eu$^{2+}$ phase was fabricated by conventional firing techniques under reducing atmosphere and its photoluminescence properties are studied with varying Eu concentration and phost-annealing temperature under air atmosphere. This phosphors were well crystallized with particle size in the range of 3~5um and emitted a blue light at a dominent wavelength 450nm for 254nm UV irradiation. The concentration quenching wit Eu$^{2+}$ was that with increasing Eu concentration the energy transfer between the activator ions steadily improves, so that the excitation energy is transported over larger distances through the lattice before luminescence can occur. Thermal quenching also occurred in this phosphor means that in a host lattice with the $\beta$-alumina structure the bond of an Eu$^{2+}$ ion with the nearest-neighbour oxygen ion is much stronger than in a lattice with the magnetoplumbite structure.cture.

• Proceedings of the Korean Powder Metallurgy Institute Conference
• /
• 2006.09a
• /
• pp.169-170
• /
• 2006

Advanced melting technology is now being employed in the manufacture of stainless steel powders. The new process currently includes electric arc furnace (EAF) technology in concert with Argon Oxygen Decarburization (AOD), High Performance Atomizing (HPA) and hydrogen annealing. The new high performance-processing route has allowed the more consistent production of existing products, and has allowed enhanced properties, such as improved green strength and green density. This paper will review these processing changes along with the potential new products that are being developed utilizing this technology. These include high strength stainless steels such as duplex and dual phase as well as stainless steel powders used in high temperature applications such as diesel filters and fuel cells.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1999.11a
• /
• pp.224-227
• /
• 1999

Ferroelectric Pb(Zr$\sub$0.52/Ti$\sub$0.48/)O$_3$ thin films were fabricated by pulsed laser deposition, mainly varying process conditions such as substrate temperature, oxygen pressure, and laser energy, PZT films annealed at more than 600$^{\circ}C$ were crystallized into pure perovskite phases regardless of deposition temperatures. Lower deposition temperature of 400$^{\circ}C$ accompanied with post-annealing at 650$^{\circ}C$ resulted in denser microstructures with extremely small grains compated to those of thin films annealed at higher deposition temperatures. Hysteresis curves of thin film with small grains exhibitied good squareness and low leakage characteristics.

• Journal of the Korean Vacuum Society
• /
• v.17 no.2
• /
• pp.130-137
• /
• 2008

$La_{0.7}Sr_{0.3}MnO_3$ films were deposited on $SiO_2$/Si and Si substrates annealed at $350^{\circ}C$ by rf magnetron sputtering. The oxygen gas flow rates were varied as 0, 40, and 80 sccm. Without post annealing process, $La_{0.7}Sr_{0.3}MnO_3$ thin films on $SiO_2$/Si and Si substrates were polycrystalline with (100), (110), and (200) growth planes. The grain size of $La_{0.7}Sr_{0.3}MnO_3$ thin films was increased with increasing oxygen gas flow rate. The sheet resistance of $La_{0.7}Sr_{0.3}MnO_3$ thin films was decreased with oxygen flow rate due to the increased grain size which induced a reduction of grain boundary. TCR (temperature coefficient of resistance) values of $La_{0.7}Sr_{0.3}MnO_3$ thin films were obtained from -2.0% to -2.2%.

• Proceedings of the KIEE Conference
• /
• 2001.11a
• /
• pp.23-25
• /
• 2001

In this work, the $Ta_2O_5$ thin films were deposited on Pt/n-Si substrate by reactive magnetron sputtering and the RTA treatment at temperatures range from 650 to $750^{\circ}C$ in $O_2$ and vacuum. X-ray diffraction analysis, FE SEM, dielectric properties and leakage current density have been used to study the structural and electrical properties of the $Ta_2O_5$ thin films. XRD result showed that as- deposited films were amorphous and the annealed films crystallized (<$700^{\circ}C$) into ${\beta}-Ta_2O_5$. The crystallinity increased with temperature in terms of an increase in the intensity of the diffracted peaks(${\beta}-Ta_2O_5$) and annealing in oxygen reduced defect dang1ing Ta-O bonds. As deposited $Ta_2O_5$ films show the leakage current density $10^{-7}$ to $10^{-8}$ (A/$cm^2)$ at low electric fields (<200 kV/cm) However, it was found leakage current density of $Ta_2O_5$ thin films decreased with $O_2$ ambient annealing. The dielectric constant of the as deposited $Ta_2O_5$ thin films was ${\varepsilon}_r$ $9{\sim}11$ but the dielectric constant was increased after RTA treatment in $O_2$ ambient more then in vacuum.

• Bulletin of the Korean Chemical Society
• /
• v.34 no.7
• /
• pp.2067-2072
• /
• 2013

Hydrogen ($H_2$) treatment using a two-step $TiO_2$ nanotube (TONT) film was performed under various annealing temperatures from $350^{\circ}C$ to $550^{\circ}C$ and significantly influenced the extent of hydrogen treatment in the film. Compared with pure TONT films, the hydrogen-treated TONT (H:TONT) film showed substantial improvement of material features from structural, optical and electronic aspects. In particular, the extent of enhancement was remarkable with increasing annealing temperature. Light absorption by the H:TONT film extended toward the visible region, which was attributable to the formation of sub-band-gap states between the conduction and valence bands, resulting from oxygen vacancies due to the $H_2$ treatment. This increased donor concentration about 1.5 times higher and improved electrical conductivity of the TONT films. Based on these analyses and results, photoelectrochemical (PEC) performance was evaluated and showed that the H:TONT film prepared at $550^{\circ}C$ exhibited optimal PEC performance. Approximately twice higher photocurrent density of 0.967 $mA/cm^2$ at 0.32 V vs. NHE was achieved for the H:TONT film ($550^{\circ}C$) versus 0.43 $mA/cm^2$ for the pure TONT film. Moreover, the solar-to-hydrogen efficiency (STH, ${\eta}$) of the H:TONT film was 0.95%, whereas a 0.52% STH efficiency was acquired for the TONT film. These results demonstrate that hydrogen treatment of TONT film is a simple and effective tool to enhance PEC performance with modifying the properties of the original material.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.44 no.11
• /
• pp.20-25
• /
• 2007

In this paper, It was reported the dielectric constant in organic inorganic hybrid silica material such as SiOC film modeling of bond structure by annealing in organic properties. The organic inorganic hybrid silica material were deposited using bis-trimethylsilymethane (BTMSM, [(CH3)3Si]2CH2) and oxygen gas precursor by a plasma chemical vapor deposition (CVD). The organic inorganic hybrid silica material have three types according to the deposition condition. The dielectric constant of the films were performed MIS(Al/Si-O-C film/p-Si) structure. The C 1s spectra in organin inorganic silica materials with the flow rate ratio of O2/BTMSM=1.5 was organometallic carbon with the peak 282.9 eV by XPS. It means that organometallic carbon component is the cross-link bonding structure with good stability. The dielectric constant was the lowest at annealed films with cross-link bonding structure.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2016.02a
• /
• pp.402.1-402.1
• /
• 2016

The performance of solid oxide fuel cells (SOFCs) is directly related to the electrocatalytic activity of composite electrodes in which triple phase boundaries (TPBs) of metallic catalyst, oxygen ion conducting support, and gas should be three-dimensionally maximized. The distribution morphology of catalytic nanoparticle dispersed on external surfaces is of key importance for maximized TPBs. Herein in situ grown nickel nanoparticle onto the surface of fluorite oxide is demonstrated employing gadolium-nickel co-doped ceria ($Gd0.2-xNixCe0.8O2-{\delta}$, GNDC) by reductive annealing. GNDC powders were synthesized via a Pechini-type sol-gel process while maximum doping ratio of Ni into the cerium oxide was defined by X-ray diffraction. Subsequently, NiO-GNDC composite were screen printed on the both sides of yttrium-stabilized zirconia (YSZ) pellet to fabricate the symmetrical half cells. Electrochemical impedance spectroscopy (EIS) showed that the polarization resistance was decreased when it was compared to conventional Ni-GDC anode and this effect became greater at lower temperature. Ex situ microstructural analysis using scanning electron microscopy after the reductive annealing exhibited the exsolution of Ni nanoparticles on the fluorite phases. The influence of Ni contents in GNDC on polarization characteristics of anodes were examined by EIS under H2/H2O atmosphere. Finally, the addition of optimized GNDC into the anode functional layer (AFL) dramatically enhanced cell performance of anode-supported coin cells.