• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.130-130
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• 2010

Thin Si films were grown by a plasma-enhanced chemical vapor deposition (PECVD, SNTEK, Korea) system. Two different deposition condition were applied and formed a fully amorphous Si (a-Si) film and a micromorph mixing of microcrystalline Si (mc-Si) and a-Si film. Under one sun illumination, the micromorph device provided the enhanced open circuit voltage and fill factor values. It presents the fabrication of the micromorph Si film and the a-Si film by modulating a deposition condition. The performances of the Si thin film Schottky solar cells are discussed.

• Transactions of Materials Processing
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• v.30 no.3
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• pp.109-118
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• 2021

Recently, there has been an increased interest in the remanufacturing of mechanical parts using metal additive manufacturing processes in regards to resource recycling and carbon neutrality. DED (directed energy deposition) process can create desired metallic shapes on both even and uneven substrate via line-by-line deposition. Hence, DED process is very useful for the repair, retrofit and remanufacturing of mechanical parts with irregular damages. The objective of the current paper is to investigate the effects DED process parameters, including the effects of power and the scan speed of the laser, on deposition and residual stress characteristics for remanufacturing of mechanical parts using experiments and finite element analyses (FEAs). AISI 1045 is used as the substrate material and the feeding powder. The characteristic dimensions of the bead shape and the heat affected zone (HAZ) for different deposition conditions are obtained from the experimental results. Efficiencies of the heat flux model for different deposition conditions are estimated by the comparison of the results of FEAs with those of experiments in terms of the width and the depth of HAZ. In addition, the influence of the process parameters on residual stress distributions in the vicinity of the deposited region is investigated using the results of FEAs. Finally, a suitable deposition condition is predicted in regards to the bead formation and the residual stress.

• Journal of the Korean institute of surface engineering
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• v.36 no.5
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• pp.393-397
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• 2003

The effects of the composition and additives on the blackening and deposition rate of electroless Ni-Zn plating have been examined. Hydrazine resulted in lower sheet resistance of the deposit than sodium hypophosphite. Zinc concentration more than 15 wt% and small amount of ammonium sulfate in the deposits were needed in obtaining Ni-Zn deposit with a black color. An optimum condition was obtained for the black Ni-Zn deposit at an appreciable deposition rate.

• Journal of the Korean institute of surface engineering
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• v.31 no.3
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• pp.165-170
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• 1998

Deposition of diamond on silicon substrates has been performed by RF HPCVD (Helicon Plasma Chemical Vapor Deposition) from methane-hydrogen gas mixture. Growth properties and deposition condition conditions have been studies as functions of substrate temperature ($750^{\circ}C$~$850^{\circ}C$). Si p-type (100) wafers were used as a substrate. The chharecterizations of the gaind thin films by SEM, AFM and Raman seattring are diamond crystallites which include disordered graphit.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.318.1-318.1
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• 2013

Nowadays Cu2ZnSnS4 (CZTS) solar cell is attracting a lot of attention as a strong alternative to CIGS solar cell due to nontoxic and inexpensive constituent elements of CZTS. From various processes for the fabrication of CZTS solar cell, solution-based deposition of CZTS thin films is well-known non-vacuum process and many researchers are focusing on this method because of large-area deposition, high-throughput, and efficient material usage. Typically the solution-based process consists of two steps, coating of precursor solution and annealing of the precursor thin films. Unlike vacuum-based deposition, precursor solution contains unnecessary elements except Cu, Zn, Sn, and S in order to form high quality precursor thin films, and thus the precise control of precursor thin film preparation is essential for achieving high efficient CZTS solar cells. In this work, we have investigated the effect of preparation condition of CZTS precursor thin films on the performance of CZTS solar cells. The composition of CZTS precursor solution was controlled for obtaining optimized chemical composition of CZTS absorber layers for high-efficiency solar cells. Pre-annealing process of the CZTS precursor thin films was also investigated to confirm the effect of thermal treatment on chemical composition and carbon residues of CZTS absorber layers. The change of the morphology of CZTS precursor thin film by the preparation condition was also observed.

• 한국초전도학회:학술대회논문집
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• v.9
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• pp.34-37
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• 1999

We have fabricated YBCO/STO/YBCO multilayer by the pulsed laser deposition method varing the deposition condition of insulating STO layer. Superconducting properties of both YBCO layers are sensitively affected by the deposition condition of STO layer. We obtained the upper YBCO layer of T$_{c(zero)}\;{\sim}\;$90 K with a good reproducibility, however, T$_{c(zero)}$ of lower YBCO layer was decreased to about 80 K maybe due to the oxygen loss during the deposition of STO layer. Superconducting properties of both YBCO layers at every fabrication step were measured in order to study the reason for the deterioration of superconducting properties.

• Journal of the Korean institute of surface engineering
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• v.44 no.5
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• pp.185-189
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• 2011

$Cu_2ZnSnSe_4$ thin films for solar absorber application were prepared by pulsed laser deposition of a synthesized $Cu_2ZnSnSe_4$ compound target. The film's composition revealed that the deposited films possess an identical composition with the target material. Further film compositional control toward a stoichiometric composition was performed by optimizing substrate temperature, deposition time and target rotational speed. At the optimum condition, X-ray diffraction patterns of films showed that the films demonstrated polycrystalline stannite single phase with a high degree of (112) preferred orientation. The absorption coefficient of $Cu_2ZnSnSe_4$ thin films were above 104 cm.1 with a band gap of 1.45 eV. At an optimum condition, films were identified as a p type semiconductor characteristic with a resistivity as low as $10^{-1}{\Omega}cm$ and a carrier concentration in the order of $10^{17}cm^{-3}$.

• Progress in Superconductivity and Cryogenics
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• v.4 no.2
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• pp.5-10
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• 2002

Deposition condition of NiO that is one of Possible buffer layers for YBCO coated conductors was studied. NiO was deposited on textured Ni substrates by a MOCVD (metal-organic chemical vapor deposition) method. The degree of texture, and the surface roughness were analyzed by X-ray Pole figure, atomic force microscope and scanning electron microscope. The (111) and (200) textures were competitively developed , depending on an oxygen partial Pressure(PO2) and deposition temperature (Tp). The (200) textured NiO layer was deposited at Tp=450~47$0^{\circ}C$ and PO2= 1.67 Torr Out-of-Plane ($\omega$-scan) and in-plane ($\Phi$-scan) textures of the (200) NiO films were as good as 10.34$^{\circ}$ and 10.00$^{\circ}$ respectively The AFM surface roughness of NiO was in the range of 3~4.5 nm at PO2=0.91~3.34 Torr and at Tp=47$0^{\circ}C$ , and in the range of 3~13 nm at TP=450~53$0^{\circ}C$ and at PO2=1.67 Torr.

• Progress in Superconductivity and Cryogenics
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• v.16 no.4
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• pp.36-39
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• 2014

We report on the superconducting and structural characteristics of Pb-based alloy ($Pb_{0.9}In_{0.1}$, $Pb_{0.8}In_{0.2}$ and $Pb_{0.85}Bi_{0.15}$) thin films, depending on the film deposition rate. The maximum critical magnetic field strength of $Pb_{0.85}Bi_{0.15}$ is almost six times larger than that of $Pb_{0.9}In_{0.1}$, and more rapid growth of the film enhances the critical magnetic field strength even for the same alloy material. Scanning electron microscopy inspection indicates that lower deposition rate condition is vulnerable to the formation of void structure in the film. Topographic images using atomic force microscopy are useful to optimize the deposition condition for the growth of smooth superconducting film. Our work can be utilized for future studies on hybrid superconducting devices using low-dimensional nanostructures.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05a
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• pp.153-157
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• 2002

This paper deals with the relationships between MgO manufacturing condition and misfiring at low temperature. The characteristics of MgO are affected by substrate temperature and MgO deposition current. In this study. the. substrate temperature was varied from $100^{\circ}C$ to $200^{\circ}C$. And the MgO deposition current was varied from 5mA to 20mA. As a result. the misfiring at low temperature was decreased in the panels with substrate temperature $200^{\circ}C$ and MgO deposition current 5mA. These results may be explained that the higher substrate temperature and lower MgO deposition current makes the denser film formation.