• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.9
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• pp.931-935
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• 2012

In this study, we fabricate and investigate low-temperature solid oxide fuel cells with a ceramic substrate/porous metal/ceramic/porous metal structure. To realize low-temperature operation in solid oxide fuel cells, the membrane should be fabricated to have a thickness of the order of a few hundreds nanometers to minimize IR loss. Yttrium-doped barium zirconate (BYZ), a proton conductor, was used as the electrolyte. We deposited a 350-nm-thick Pt (anode) layer on a porous substrate by sputter deposition. We also deposited a 1-${\mu}m$-thick BYZ layer on the Pt anode using pulsed laser deposition (PLD). Finally, we deposited a 200-nm-thick Pt (cathode) layer on the BYZ electrolyte by sputter deposition. The open circuit voltage (OCV) is 0.806 V, and the maximum power density is 11.9 mW/$cm^2$ at $350^{\circ}C$. Even though a fully dense electrolyte is deposited via PLD, a cross-sectional transmission electron microscopy (TEM) image reveals many voids and defects.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.729-732
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• 2001

In this study, the effect of oxygen partial pressure on the electrical properties of vanadium oxide(VO$_{x}$) thin films were investigated. The thin films were prepared by r.f. magnetron sputtering from V$_2$O$_{5}$ target in a gas mixture of argon and oxygen. The oxygen partial pressure ratio is changed from 0% to 8%. I-V characteristics were distinguished between linear and nonlinear region. In the low field region the conduction is due to Schottky emission, while at high fields it changes to Fowler-Nordheim tunneling type conduction. The conductivity measurements have shown an Arrhenius dependence of the conductivity on the temperature.ure.

• Bulletin of the Korean Chemical Society
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• v.35 no.11
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• pp.3299-3302
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• 2014

The In2S3 thin films of tetragonal structure and In2O3 films of cubic structure were synthesized by a spin coating method from the organometallic compound precursor triethylammonium indium thioacetate ($[(Et)_3NH]^+[In(SCOCH_3)_4]^-$; TEA-InTAA). In order to determine the electron mobility of the spin-coated TEA-InTAA films, thin film transistors (TFTs) with an inverted structure using a gate dielectric of thermal oxide ($SiO_2$) was fabricated. These devices exhibited n-channel TFT characteristics with a field-effect electron mobility of $10.1cm^2V^{-1}s^{-1}$ at a curing temperature of $500^{\circ}C$, indicating that the semiconducting thin film material is applicable for use in low-cost, solution-processed printable electronics.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.143-146
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• 2009

The metal-supported SOFC has beed developed as a new concept of SOFC which has higher mechanical strength. However, the mass transfer rate in this type of SOFC may be decreased due to the contact layer and the support layer and that can cause the low performance. Therefore, numerical analysis of the heat and mass transfer characteristics in a metal-supported solid oxide fuel cell(SOFC) is studied in this paper. Governing equations and electrochemical equations are calculated simultaneously. And the numerical results are compared with the experimental results for the code validation. The current density, temperature, and pressure drop are suggested as numerical results.

• Korean Journal of Optics and Photonics
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• v.11 no.3
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• pp.152-157
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• 2000

Post-deposition vacuum annealing effects in electron-bearn-evaporated indium tin oxide (ITO) films have been investigated by the change of transmittance, sheet resistance and crystalline structure with annealing temperature ( $200-335^{\circ}C$) and oxygen partial pressure ($1\times^10^{-5}-1$\times10^{-4} torr$) in air and vacuum. The sarnples were polycrystalline films with a preferred orientation in the (222) plan. High quality films with sheet resistance as low as 62 Q/O and transmittance over 99% (absentee layer at 500 nm) have been obtained by suitably controlling the vacuum annealing pararneters.neters.

• 한국정보디스플레이학회:학술대회논문집
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• 2000.01a
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• pp.63-64
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• 2000

The low-temperature Si oxidation kinetics by inductively coupled oxygen plasma has been studied. Linear rate constants had negative values when the oxide growth rate was described by linear-parabolic growth law. The analysis of transverse-optical mode frequencies and etch rates indicated that the density of surface oxide was lower than that of bulk oxide. The oxidation kinetics could be explained qualitatively by assuming a surface layer with larger diffusion coefficient and a bulk layer with smaller diffusion coefficient.

• Carbon letters
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• v.13 no.1
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• pp.48-50
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• 2012

Mass production of graphene-based materials, which have high specific surface area, is of importance for industrial applications. Herein, we report on a facile approach to produce thermally modified graphene oxide (TMG) in large quantities. We performed this experiment with a hot plate under environments that have relatively low temperature and no using inert gas. TMG materials showed a high specific surface area (430 $m^2g^{-1}$). Successful reduction was confirmed by elemental analysis, X-ray photoelectron spectroscopy, thermogravimetic analysis, and X-ray diffraction. The resulting materials might be useful for various applications such as in rechargeable batteries, as hydrogen storage materials, as nano-fillers in composites, in ultracapacitors, and in chemical/bio sensors.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.32 no.12
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• pp.963-969
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• 2008

The performance behavior of solid oxide fuel cell using $H_2$ and CO as fuels was investigated. The power densities and impedance results showed a little variation as the ratio of $H_2$ and CO changed. However, when the pure CO was used as a fuel, area specific resistance (ASR), especially low frequency region, was increased. This might be due to carbon deposition on anode. The maximum power density was 60% lower using CO than using $H_2$. Carbon deposition reduced after constant current was applied. The SOFC performance was recovered from the carbon deposition after applying constant current during 100h.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.4
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• pp.261-266
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• 1998

In developing the high density memory device, the etching of fine pattern is becoming increasingly important. Therefore, definition of ultra fine line and space pattern and minimization of damage and contamination are essential process. Also, the high density plasma in low operating pressure is necessary. The candidates of high density plasma sources are electron cyclotron resonance plasma, helicon wave plasma, helical resonator, and inductively coupled plasma. In this study, planar type magnetized inductively coupled plasma etcher has been built. The density and temperature of Ar plasma are measured as a function of rf power, flow rate, external magnetic field, and pressure. The oxide etch rate and selectivity to polysilicon are measured as the above mentioned conditions and self-bias voltage.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.122-123
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• 2006

Tin oxide nanoparticles (n-SnO and $n-SnO_2$) were synthesized by the inert gas condensation (IGC) method under dynamic gas flow of oxygen and argon at various conditions. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) method were used to analysis the size, shape and crystal structure of the produced powders. The synthesized particles were mostly amorphous and their size increased with increasing the partial pressure of oxygen in the processing chamber. The particles also became broader in size when higher oxygen pressures were applied. Low temperature annealing at $320^{\circ}C$ in air resulted to crystallization of the amorphous n-SnO particles to $SnO_2$.