• Environmental Engineering Research
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• 제18권3호
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• pp.145-150
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• 2013

Optimal preparation guidelines of a cathode catalyst layer by non-precious metal catalysts were evaluated based on electrochemical performance in single-chamber microbial fuel cells (MFCs). Experiments for catalyst loading rate revealed that iron(II) phthalocyanine (FePc) can be a promising alternative, comparable to platinum (Pt) and cobalt tetramethoxyphenylporphyrin (CoTMPP), including effects of substrate concentration. Results showed that using an optimal FePc loading of $1mg/cm^2$ was equivalent to a Pt loading of $0.35mg/cm^2$ on the basis of maximum power density. Given higher loading rates or substrate concentrations, FePc proved to be a better alternative for Pt than CoTMPP. Under the optimal loading rate, it was further revealed that 40 wt% of FePc to carbon support allowed for the best power generation. These results suggest that proper control of the non-precious metal catalyst layer and substrate concentration are highly interrelated, and reveal how those combinations promote the economic power generation of single-chamber MFCs.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 한국결정성장학회 1998년도 PROCEEDINGS OF THE 14TH KACG TECHNICAL MEETING AND THE 5TH KOREA-JAPAN EMGS (ELECTRONIC MATERIALS GROWTH SYMPOSIUM)
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• pp.57-60
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• 1998

Lean zirconate titanate (PZT) is an attractive material for the memory device applications. We have investigated Pt and{{{{ { RuO}_{2 } }}}} as a botton electrode for a device application of PZT thin film. The bottom electrodes were prepared by using an RF magnetron sputtering method. The substrate temperature influenced the resistivity of Pt and {{{{ { RuO}_{2 } }}}} a s well as the film crystal structure. XRD examination shows that a preferred(111) orientations for the substrate temperature of 30$0^{\circ}C$. From the XRD and AFM results, we recommend the substrate temperature of 30$0^{\circ}C$ for the bottom electrode growth. We investigated and anneal temperature effect because Perovskite PZT structure is recommended for the memory device applications and the structural transformation is occurred only after and elevated heat treatment. As post anneal temperature was increased from RT to $700^{\circ}C$, the resistivity of Rt and {{{{ { RuO}_{2 } }}}} w as decreased. Surface morphology was observed by AFM as a function of post anneal temperature.

• Korean Journal of Materials Research
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• 제10권4호
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• pp.282-289
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• 2000

$PbTiO_3$ films were fabricated by electron cyclotron resonance plasma enhanced chemical vapor deposition(ECR-PECVD). Deposition characteristics of $PbTiO_3$films on $RuO_2$ and Pt substrates were investigated with varying the flow rate of metalorganic source and substrate temperature. The residence time of Pb-oxide molecules in much longer on $RuO_2$ than on Pt substrate, while the perovskite nucleation is more difficult on $RuO_2$ than on Pt substrate. Therefore, the process conditions to obtain the single perovskite $PbTiO_3$ phase are more restricted on $RuO_2$ than on Pt substrates. An introduction of Ti-oxide seed layer increases perovskite nucleation density and thus enlarges the process window to obtain the single perovkite phase. The introduction of Ti-oxide seed layer make the PZT film that Ti-components of $PbTiO_3$ are partially substituted with Zr atoms have single perovskite phase for the wide range of Zr/(Zr+Ti) concentration ratios.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 한국전기전자재료학회 1997년도 추계학술대회 논문집
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• pp.331-334
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• 1997

The electrical and physical charateristics of aluminum oxide and Pt thin films on it, deposited by reactive sputtering and DC magnetron sputtering, respectively, were analysed with increasing annealing temperature(400~80$0^{\circ}C$) by four point probe, SEM and XRD. Under $600^{\circ}C$ of annealing temperature, aluminum oxide had the properties of improving Pt adhesion to SiO$_2$and insulation without chemical reaction to Pt thin films and the resistivity of Pt thin finns was improved. But these properties of aluminum oxide and Pt thin finns on it were degraded over $700^{\circ}C$ of annealing temperature because aluminum oxide was changed into metal aluminum and then reacted to Pt thin films deposited on it. The thermal characteristics of Pt micro heater were analysed with Pt-RTD integrated on the same substrate. In the analysis of properties of Pt micro heater. active area was smaller size, Pt micro heater had better thermal characteristics. Temperature of Pt micro heater fabricated on membrane was up to 34$0^{\circ}C$ with 1.2watts of the heating power due to reduction of the external thermal loss.

• Journal of the Korean Ceramic Society
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• 제37권3호
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• pp.263-270
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• 2000

The Pt/copper oxide/n-Si electrodes were fabricated by depositing copper oxide thin film of 500${\AA}$ and very thin Pt layer on the n-type (100) Si substrate. hotoelectrochemical properties and stability profiles of the electrodes were investigated as a function of deposition time of Pt layer. As the deposition time of Pt layer increased up to 10 seconds, the photocurrent and quantum efficiency were increased and then decreased with further depositing time. The better cell stability was observed for the electrode with longer deposition time. The improvements in above photoelectrochemical properties indicate that Pt layer acts as a catalyst layer at electrode/electrolyte interface as well as a protective layer. The decreasing tendency of the photocurrent and efficiency for the electrode with Pt layer deposited above 20 seconds was explained as an increases in probbility of electron-hole pair recombination and also the absorbing photon loss at electrode surface due to the excessive thickness of Pt layer. The results were confirmed by impedance spectroscopy, mutiple cycle voltammograms and microstructural analyses.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.2
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• pp.718-721
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• 2004

The $(Sr_{0.9}Ca_{0.1})TiO_3$(SCT) thin films are deposited on Pt-coated electrode$(Pt/TiN/SiO_2/Si)$ using RF sputtering method at various substrate temperature. The optimum conditions of RF power and $Ar/O_2$ ratio were 140[W] and 80/20, respectively. Deposition rate of SCT thin films was about $18.75[{\AA}/min]$. The crystallinity of SCT thin films were increased with increase of substrate temperature in the temperature range of $100\sim500[^{\circ}C]$. The dielectric constant of SCT thin films were increased with the increase of substrate temperature, and changed almost linearly in temperature ranges of $-80\sim+190[^{\circ}C]$. The current-voltage characteristics of SCT thin films showed the increasing leakage current as the substrate temperature increases.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 한국전기전자재료학회 2000년도 추계학술대회 논문집
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• pp.217-220
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• 2000

The SrBi$_2$Ta$_2$O$\_$9/(SBT) thin films are deposited on Pt-coated electrode(Pt/TiO$_2$/SiO$_2$/Si) using RF sputtering method. The SBT thin films deposited on substrate at 400-500[$^{\circ}C$]. SBT thin film deposited on Pt-coated electrodes have the cubic perovskite structure and polycrystalline state. With increasing annealing temperature from 600[$^{\circ}C$] to 850[$^{\circ}C$], flourite phase was crystallized to 650[。 and Bi-layered perovskite phase was crystallize ed above 700[$^{\circ}C$]. The maximum remnant polarization and the coercive electric field is 11.73[${\mu}$C/$\textrm{cm}^2$], 85[kV/cm] respectively at annealing temperature of 750[$^{\circ}C$]. The fatigue characteristics of SBT thin films deposited on Pt/TiO$_2$/SiO$_2$/Si substrate did not change up to 10$\^$10/ switching cycles.

• Proceedings of the Korean Magnestics Society Conference
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• 한국자기학회 2000년도 International Symposium on Magnetics The 2000 Fall Conference
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• pp.352-362
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• 2000

In this study, effects of novel VMn underlayer on magnetic properties of CoCrPt/VMn longitudinal medium was studied and compared with those of CoCrPt/Cr medium. It was found that the VMn film had (200) preferred orientation and the lattice constant was about 0.2967 nm, which is slightly larger than that of the Cr, 0.2888 nm. The grain size of VMn film was 9.3 nm at 30 nm thickness, and this is about 38 % smaller than that of a similarly deposited Cr film. The CoCrPt/VMn films showed higher coercivity in comparison with the CoCrPt/Cr films. The coercivity increase seems to be attributed to the increased Co (11.0) texture, improved lattice matching between Co (11.0) and VMn (200), and lower stacking fault density. Mn must have diffused into the CoCrPt magnetic layer more uniformly rather than preferentially along grain boundaries this reduced Ms at higher substrate temperature

• Journal of the Korean Vacuum Society
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• 제7권1호
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• pp.17-23
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• 1998

$Pb(Fe_{0.5}Nb_{0.5}O_3(PFN)$ thin films were prepared by rf magnetron co-sputtering method on $SiO_2/Si$, ITO/glass, and $Pt/Ti/SiO_2/Si$ substrates and post-annealed at the $N_2$ atmosphere by RTA(rapid thermal annerling). The degree of crystallinity of PFN films was identified on various substrates. Electrical properties of PFN films was characterized for $Pt/PFN/Pt/Ti/SiO_2/Si$ structure. The composition of PFN films was estimated by EPMA (electron probe micro analysis). PFN films would be crystallized better to perovskite phase on ITO/glass substrate than $SiO_2/Si$ substrate. This may be induced by the deformation of Pb deficient pyrochlore phase due to Pb diffusion into $SiO_2/Si$ substrate. PFN films on $Pt/Ti/SiO_2/Si$ substrate. PFN films with 5-10% Pb excess were crystallized to perovskite phase from $500^{\circ}C$ temperature. In summary, we show that Pb composition and annealing temperature were critically influenced on crystallinity to perovskite phase. When PFN film with 17% Pb excess was annealed at $600^{\circ}C$ at the $N_2$ atmosphere for 300kV/cm and 88. Its remnant polarization coercive field $2.0 MC/cm^2$ and 144kV/cm, respectively.

• Journal of Sensor Science and Technology
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• 제7권1호
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• pp.45-50
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• 1998

Platinum-Cobalt alloy thin films were deposited on $Al_{2}O_{3}$ substrate by magnetron cosputtering for RTD temperature sensors. We made Pt-Co alloy resistance patterns on the $Al_{2}O_{3}$ substrate by lift-off method and investigated the physical and electrical characteristics of these films under various conditions, the input power, working vacuum, annealing temperature and time, and also after annealing these films. The resistivity and sheet resistivity of these films were decreased with increasing the annealing temperature. At input power of Pt : $4.4\;W/cm^{2}$, Co : $6.91\;W/cm^{2}$, working vacuum of 10 mTorr and annealing conditions of $800^{\circ}C$ and 60 min, the resistivity and sheet resistivity of Pt-Co thin films was $15{\mu}{\Omega}{\cdot}cm$ and $0.5{\Omega}/{\square}$, respectively and the TCR value of Pt-Co alloy thin films with thickness of $3000{\AA}$ were $3740ppm/^{\circ}C$ in the temperature range of $25{\sim}600^{\circ}C$. These results indicate that Pt-Co alloy thin films have potentiality for the RTD temperature sensors.