• The Korean Journal of Ceramics
• /
• v.3 no.4
• /
• pp.263-268
• /
• 1997

RuO$_3$ thin films were deposited on Si(100) substrate at low temperatures by hot-wall metalorganic chemical vapor deposition. Bis(cyclopentadienyl) ruthenium, Ru$(C_5H_5)_2$, was used as the precursor RuO$_2$single phase was obtained at a low deposition temperature of 25$0^{\circ}C$ and the crystallinity of RuO$_2$thin films improved with increasing deposition temperature. RuO$_2$thin films grow perpendicularly to the substrate and show the columnar structure. The grain size of RuO$_2$films drastically increases with increasing the deposition temperature. The resistivity of the 180 nm-thick RuO$_2$thin films deposited at 27$0^{\circ}C$ was 136 $\mu$$\Omega$-cm and increased with decreasing film thickness. SrBi$_2Ta_2O_4$ thin films deposited by rf magnetron sputtering on the RuO$_2$bottom electrodes showed a fatigue-free characteristics up to ~10$^10$ cycles under 5 V bipolar square pulses and the remanent polarization, 2 P$_r$ and the coercive field, 2 E, were 5.2$\mu$C/$\textrm{cm}^2$ and 76.0 kV/cm, respectively, for an applied voltage of 5 V The leakage current density was about 7.0$\times$10$^{-6}$ A/$\textrm{cm}^2$ at 150 kV/cm.

• Applied Chemistry for Engineering
• /
• v.29 no.1
• /
• pp.18-21
• /
• 2018

We report on the simple preparation method of large-scale structured catalysts by temperature-regulated chemical vapor deposition with a high cell-density ceramic honeycomb monolith. And the feasibility for dry reforming of methane catalysts was evaluated. The NiO/Cordierite (CDR) catalyst was prepared by controlling coating conditions at each temperature step, leading to a conformal deposition of NiO inside the cordierite honeycomb monolith with the cell density of 600 cpsi. The catalytic conversion of $CH_4$ and $CO_2$ for dry reforming of methane were about 83% and 90% with gas hourly space velocity of $10,000h^{-1}$ at $800^{\circ}C$, respectively. As a result, it exhibited that the temperature-regulated chemical vapor deposition method can be expedient for the preparation of large-scale structured catalysts.

• Transactions on Electrical and Electronic Materials
• /
• v.3 no.1
• /
• pp.14-17
• /
• 2002

The effects of substrate temperatures and annealing temperatures on the microstructures and ferroelectric properties of PbZ $r_{0.52}$ $Ti_{0.48}$ $O_3$(PZT) thin fims prepared by pulsed laser deposition (PLD) were investigated. For this purpose, the PZT films were deposited at various substrate temperatures (400~$600^{\circ}C$) with post annealing process in oxygen atmosphere. The single perovskite phase was formed at the deposition temperature of 500 to 55$0^{\circ}C$ without post annealing and the PZT films deposited below 50$0^{\circ}C$ formed the single phase with post annealing at $650^{\circ}C$. The grain size of the films increased and the grain boundary of the films was clearly defined as the substrate temperature increased from 400 to 55$0^{\circ}C$. The remnant polarization (Pr) and the coercive field (Ec) of the films deposited at 55$0^{\circ}C$ and annealed at $650^{\circ}C$ were 34.3 $\mu$C/c $m^2$and 60.2 kV/cm, respectively.y.y.

• Journal of the Korean Ceramic Society
• /
• v.46 no.3
• /
• pp.234-241
• /
• 2009

In this study, CNT/$TiO_2$ composites derived from various titanium alkoxides and multiwalled carbon nanotubes (MWCNTs) were synthesized and characterized. Surface areas and pore volumes of the CNT/$TiO_2$ samples showed catastrophic decrease due to deposition of titanium compounds. Scanning electron microscopy (SEM) results indicated that the MWCNTs were homogenously decorated and well-dispersed onto/into the composites without apparent agglomeration of $TiO_2$ particles. In the X-ray diffraction (XRD) patterns, peaks of anatase and rutile phase were observed. The energy dispersive X-ray spectroscopy (EDX) spectra revealed the presence of major elements such as C and O with strong Ti peaks. According to the photocatalytic results, MB removal by a treatment with CNT/$TiO_2$ composites seems to have an excellent removal effect as order of CTIP, CTNB and CTPP composites due to a photolysis of the supported $TiO_2$, the radical reaction and the adsorptivity and absorptivity of the MWCNTs.

• Journal of the Korean Ceramic Society
• /
• v.55 no.3
• /
• pp.285-289
• /
• 2018

We synthesized silicon carbide (${\beta}-SiC$) nanowires with nano-scale diameter (30 - 400 nm) and micro-scale length ($50-200{\mu}m$) on a porous body using low-grade silica and carbon black powder by carbothermal reduction at $1300-1600^{\circ}C$. The SiC nanowires were formed by vapor-liquid-solid deposition with self-evaporated Fe catalysts in low-grade silica. We investigated the characteristics of the SiC nanowires, which were grown on a porous body with Ar flowing in a vacuum furnace. Their structural, optical, and electrical properties were analyzed with X-ray diffraction (XRD), transmission electron microscopy (TEM), and selective area electron diffraction (SAED). We obtained high-quality SiC single crystalline nanowire without stacking faults that may have uses in industrial applications.

• Journal of the Korean Ceramic Society
• /
• v.46 no.1
• /
• pp.10-15
• /
• 2009

We have fabricated silicon-rich silica thin films via RF magnetron sputtering using a SiO target. Thickness evolution and microstructure change of such $SiO_x$ (1$SiO_x$ thin films turned out to be mainly responsible for the increase of refractive index.

• Journal of the Korean Ceramic Society
• /
• v.29 no.7
• /
• pp.525-532
• /
• 1992

TiO2 fine powder was synthesized in the gas phase by chemical vapor deposition using hydrolysis of TiCl4. Content of rutile phase in the powder was investigated. Powder characteristics such as size, crystallinity and morphology were also studied by means of TEM, SEM and XRD. Rutile phase in TiO2 powder started to be formed from 100$0^{\circ}C$ and the content increased with the reaction temperature and TiCl4 concentration. As the temperature increased from 80$0^{\circ}C$ to 140$0^{\circ}C$, the primary particle size increased while secondary particle size decreased. Spherical secondary particle with fine primary crystals agglomerated was produced at low temperature of 80$0^{\circ}C$ whereas the grown primary particle being final particle size was produced at higher temperature of 140$0^{\circ}C$. Other effects of TiCl4 and H2O partial pressures on particle size were also reported in this study.

• Journal of the Korean Ceramic Society
• /
• v.41 no.12 s.271
• /
• pp.880-883
• /
• 2004

Carbon nanofibers could be selectively formed at the groove area of the MgO substrate using microwave plasma-enhanced chemical vapor deposition system. Iridium metal was used as a catalyst layer for the formation of the carbon nanofibers. The growth direction of the carbon nanofibers was vertical to the substrate surface. The selectively grown iridium-catalyzed carbon nanofibers show around $1.8V/{\mu}m$ turn-on voltage and $1.0\;mA/cm^2$ field emission current density at $2.65\;V/{\mu}m$ in the field emission measurement.

• Journal of the Korean Ceramic Society
• /
• v.38 no.8
• /
• pp.683-686
• /
• 2001

Electrochemically active lithium nickel cobalt oxide thin-film was not fabricated until now. The thin-film was deposited by RF magnetron sputtering at room temperature, and its initial phase was amorphous. By varying deposition condition, the different characteristics of thin-film were achieved. Using electrochemical analyses, the relationship between physical and electrochemical characteristics was identified. Crystallized thin-film by RTA (Rapid Thermal Annealing) was shown a good capacity and cycle property.

• Journal of the Korean Ceramic Society
• /
• v.32 no.4
• /
• pp.441-447
• /
• 1995

Ba0.65Sr0.35TiO3 (BST) thin films were deposited on Pt/SiO2/Si(100) substrate by rf magnetron sputtering. The substrate temperature changed from 35$0^{\circ}C$ to 55$0^{\circ}C$ and crystalline BST thin films were deposited above 45$0^{\circ}C$. Most of the films had (111) preferred orientation regardless of deposition temperature, but the films changed to (100) preferred orientation as gas pressure increased. The dielectric constant increased with increasing substrate temperature and film thickness, and ranged from 100 to 600 at room temperature. The leakage current increased as substrate temperature increased or as film thickness decreased.