• Korean Chemical Engineering Research
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• v.60 no.1
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• pp.7-11
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• 2022

In the membrane forming process of a proton exchange membrane fuel cell (PEMFC), drying and annealing heat treatment processes are required for performance and durability. In this study, the optimal annealing temperature for improving the durability of the polymer membrane was studied. It was annealed in the temperature range of 125~175 ℃, and thermal stability and hydrogen permeability were measured as basic data of durability at each annealing temperature. The electrochemical durability was analyzed by Fenton reaction and open circuit voltage (OCV) holding. The annealing temperature of 165 ℃ was the optimal temperature in terms of thermal stability and hydrogen permeability. In the Fenton reaction, the fluorine emission rate of the membrane annealed at 165 ℃ was the lowest, and the lifespan of the membrane annealed at 165 ℃ was the longest in the OCV holding experiment, confirming that 165 ℃ was the optimal temperature for the durability of the polymer membrane.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.476-479
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• 2000

In this study, mesh-type PECVD system was suggested to minimize the hydrogen concentration. The main structural difference between the triode system and a conventional system is that a mesh was attached to the substrate holding electrode. We investigated several conditions to compare with conventional PECVD. The main effect of mesh was to minimize the substrate damage by ion bombardment and to enhance the surface reaction to induce hydrogen desorption. It was also found that hydrogen concentration decreased but deposition rate increased as increasing applied dias. Applied DC bias enhanced sputtering process. Intense ion bombardment causes the weakly bonded hydrogen or hydrogen-containing species to leave the growing film and increased adatom mobility. Furthermore, addition of hydrogen gas enhance the surface diffusion of adatom. The structural properties of poly-Si films were analyzed by scanning electron microscopy(SEM).

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

• Transactions on Electrical and Electronic Materials
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• v.16 no.1
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• pp.34-36
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• 2015

Amorphous SiZnSnO(SZTO) thin film transistors(TFTs) have been fabricated by RF magnetron sputtering process, and they were annealed in air and in wet ambient. The electrical performance and the structure were analyzed by I-V measurement, XPS, AFM, and XRD. The results showed improvement in device performance by wet annealing process compared to air annealing treatment, because free electron was shown to be increased due to reaction of oxygen and hydrogen generating oxygen vacancy. This is understood by the generation of free electrons. We expect the wet annealing process to be a promising candidate to contributing to high electrical performance of oxide thin film transistors for backplane device applications.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.12
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• pp.18-23
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• 2009

The effect of hydrogen-nitrogen annealing on the interface trap properties of Metal-Oxide-Nitride-Oxide-Silicon (MONOS) capacitors is investigated by analyzing the capacitors' gate leakage current and the interface trap density between the Si and $SiO_2$ layer. MONOS samples annealed at $850^{\circ}C$ for 30 s by rapid thermal annealing (RTA) are treated by additional annealing in a furnace, using annealing eases $N_2$ and 2% hydrogen and 98% nitrogen gas mixture $(N_2-H_2)$ at $450^{\circ}C$ for 30 mins. Among the three samples as-deposited, annealed in $N_2$ and $N_2-H_2$, MONOS sample annealed in an $N_2-H_2$ environment is found to have the lowest increase of interface-trap density from the capacitance-voltage experiments. The leakage current of sample annealed in $N_2-H_2$ is also lower than that of sample annealed in $N_2$.

• Journal of Sensor Science and Technology
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• v.21 no.6
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• pp.425-428
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• 2012

This paper presents the fabrication and characterization of graphene based hydrogen sensors. Graphene was synthesized by annealing process of Ni/3C-SiC thin films. Graphene was transferred onto oxidized Si substrates for fabrication of chemiresistive type hydrogen sensors. Au electrode on the graphene shows ohmic contact and the resistance is changed with hydrogen concentration. Nanoparticle catalysts of Pd and Pt were decorated. Response factor and response (recovery) time of hydrogen sensors based on the graphene are improved with catalysts. The response factors of pure graphene, Pt and Pd doped graphenes are 0.28, 0.6 and 1.26, respectively, at 50 ppm hydrogen concentration.

• Transactions of the Korean hydrogen and new energy society
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• v.5 no.1
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• pp.33-39
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• 1994

The changes of hydrogenation properties of $LaNi_5$ by hydrogen charging condition were investigated using the P-C-isotherm curves, DSC(Differential Scanning Calorimetry), GC(Gas Chromatograph), X-ray diffractometer. As a results of static hydrogen charging, the hydrogen storage capacity gradually decreased and the plateau region severly slopped. Most of the degraded properties could be restored by the annealing treatment. The degradation of hydrogen storage capacity was related with the formation of stable hydride, which was not dehydrided at room temperature.

• Journal of the Korean institute of surface engineering
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• v.38 no.1
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• pp.28-36
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• 2005

In this study, the reflow characteristics of copper thin films which is expected to be used as interconnection materials in the next generation semiconductor devices were investigated. Cu thin films were deposited on the TaN diffusion barrier by metal organic chemical vapor deposition (MOCVD) and annealed at the temperature between 250℃ and 550℃ in various ambient gases. When the Cu thin films were annealed in the hydrogen ambience compared with oxygen ambience, sheet resistance of Cu thin films decreased and the breakdown of TaN diffusion barrier was not occurred and a stable Cu/TaN/Si structure was formed at the annealing temperature of 450℃. In addition, reflow properties of Cu thin films could be enhanced in H₂ ambient. With Cu reflow process, we could fill the trench patterns of 0.16～0.24 11m with aspect ratio of 4.17～6.25 at the annealing temperature of 450℃ in hydrogen ambience. It is expected that Cu reflow process will be applied to fill the deep pattern with ultra fine structure in metallization.

• Journal of the Korean institute of surface engineering
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• v.31 no.2
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• pp.117-126
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• 1998

In this study, the residue remaining on the silicon wafer during the oxide overetching using $C_4F_8/H_2$ helicon were plasmas and effects of various cleaning and annealing methods on the removal of the remaining residue were investigated. The addition of 30%$H_2$ to the C4F8 plasma increased the C/F ratio and the thickness of the residue on the etched silicon surface. Most of the residuse on the etched surfaces colud be removed by the oxygen plasmsa cleaning followed by thermal annealing over $450^{\circ}C$. Hydrogen-coataining residue formed on the silicon by 70%$C_4F_8/30%H_2$ helicon plasmas was more easily removed than hydrogen-free residue formed residue formed by $C_4F_8$ helicon wear plasmas. However, damage remaining on the silicon surface overetched using 70%$C_4F_8/30%H_2$ helicon plasmas was intensive and the degree of reocvery duing the post-annealing was lower.

• Journal of the Korean institute of surface engineering
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• v.52 no.3
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• pp.123-129
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• 2019

With recent demand for the renewable energy resources, we conducted a research on the energy conversion and storage device of supercapacitor. The hybrid graphene-zinc oxide(GZO) electrodes for the supercapacitors (SCs) were fabricated and investigated. To increase the electrical conductivity of the GZO electrode, the rapid thermal annealing(RTA) in $Ar/H_2$(10%) atmosphere was applied and the effect was examined by comparing it with RTA at Ar atmosphere. In Raman spectroscopy, the electrodes annealed at 400? in $Ar/H_2$ atmosphere showed a lower ratio of D/G peak than that of annealed at Ar atmosphere, and had a larger specific capacitance(Sc) in the cyclic voltammetry(CV), and a lower the equivalent series resistance(ESR) in the electrochemical impedance spectroscopy(EIS). The reason seems to come from the better mixing of the graphene and zinc oxide by the RTA in $Ar/H_2$(10%).