• Journal of the Korean institute of surface engineering
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• v.45 no.3
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• pp.111-116
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• 2012

Oblique angle deposition (OAD) is a physical vapor deposition method which utilizes non-normal angles between the substrate and the vaporizing source. It has been known that tilting the substrate changes the properties of the film deposited on it, which was thought to be a result of morphological change of the film. In this study, OAD has been applied to prepare single and multilayer Al films by magnetron sputtering. The magnetron sputtering source of 4 inch diameter was used to deposit the films. Al films have been deposited on Si wafers and cold-rolled steel sheets. The multilayer films were prepared by changing the tilting angle upside down at each layer interval, which means that when the first layer was deposited at an angle of $+45^{\circ}$, the second layer was deposited at an angle of $-45^{\circ}$, and vice versa. The microstructure, surface roughness and reflectance of the films were investigated using a scanning electron microscope, a surface profiler and a spectrophotometer, respectively. The corrosion resistance was measured and compared using the salt spray test. The single layer film prepared at an oblique angle of $60^{\circ}$ prepared at other angles. However, for the multilayer films, the film prepared at an oblique angle of $45^{\circ}$ showed the most compact and featureless structure. The multilayer films were found to exhibit higher corrosion resistance than the single layer films.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.399-399
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• 2008

Synthesis and characterization of ZnO structure such as nanowires, nanorods, nanotube, nanowall, etc. have been studied to multifunctional application such as optical, nanoscale electronic and chemical devices because it has a room-temperature wide band gap of 3.37eV, large exiton binding energy(60meV) and various properties. Various synthesis methods including chemical vapor deposition (CVD), physical vapor deposition, electrochemical deposition, micro-emulsion, and hydrothermal approach have been reported to fabricate various kinds of ZnO nanostructures. But some of these synthesis methods are expensive and difficult of mass production. Wet chemical method has several advantage such as simple process, mass production, low temperature process, and low cost. In the present work, ZnO nanorods are deposited on ITO/glass substrate by simple wet chemical method. The process is perfomed by two steps. One-step is deposition of ZnO seeds and two-step is growth of ZnO nanorods on substrates. In order to form ZnO seeds on substrates, mixture solution of Zn acetate and Methanol was prepared.(one-step) Seed layers were deposited for control of morpholgy of ZnO seed layers by spin coating process because ZnO seeds is deposited uniformly by centrifugal force of spin coating. The seed-deposited samples were pre-annealed for 30min at $180^{\circ}C$ to enhance adhesion and crystallinnity of ZnO seed layer on substrate. Vertically well-aligned ZnO nanorods were grown by the "dipping-and-holding" process of the substrates into the mixture solution consisting of the mixture solution of DI water, Zinc nitrate and hexamethylenetetramine for 4 hours at $90^{\circ}C$.(two-step) It was found that density and morphology of ZnO nanorods were controlled by manipulation of ZnO seeds through rpm of spin coating. The morphology, crystallinity, optical properties of the grown ZnO nanostructures were carried out by field-emission scanning electron microscopy, high-resolution electron microscopy, photoluminescence, respectively. We are convinced that this method is complementing problems of main techniques of existing reports.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.1
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• pp.25-29
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• 2012

The properties of carbon nanotube-metal hybrid nanostructures are critically dependent on the structure and chemistry of the metal-carbon nanotube interface. In this study, the interface between nickel and multi-walled carbon nanotubes (CNTs) has been investigated using physical vapor-deposited (sputter-deposited) nickel onto the surface of freestanding carbon nanotube arrays processed by nano-imprint lithography (NIL). These interfaces have been characterized by transmission electron microscopy and 3D atom probe tomography. In the nickel nanocrystals growing on the CNT surface, a metastable hexagonal $Ni_3C$-types phase appears to be stabilized. The structural stability of the nickel-CNT interface is also discussed and related to potential implications for the properties of these nanocomposites.

• Proceedings of the KIEE Conference
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• 1999.07d
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• pp.1792-1794
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• 1999

PVDF(Polyvinylidene Fluoride) thin films were prepared by using a physical vapor deposition system. Thin films were studied by X-ray diffraction (XRD), differential scanning calorimeter (DSC). The melting point$(T_m)$ of PVDF thin films increases with increasing substrate temperature. It is found that the degree of crystallinity of PVDF thin films increases from 49.8 to 67% with increasing substrate temperature from 30 to $80^{\circ}C$.

• Proceedings of the IEEK Conference
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• 2000.06b
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• pp.76-79
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• 2000

The 3$\mu\textrm{m}$-thick PVDF (Polyvinyiidene fluoride) thin film have been prepared using physical vapor deposition with electric field, and its FT-IR specrum, dielectric property and electric conduction phenomenon have been investigated. Since the characteristic peaks ate detected at 509.45 and 1273.6〔cm〕 in the FT-IR spectrum, we are confirmed that the ${\beta}$ -phase is dominant in the PVDF thin film. In the results of dielectric properties, the PVDF thin film shows anomalous dispersion, i.e. gradual decrease of dielectric constant with increase of frequency, and also that the dielectric absorption point changes from 200Hz to 7000Hz with increasing temperature of thin film, which is consistent with the Debye's theory. The activation energy (ΔH) obtained from temperature dependence of dielectric loss is 21.64 ㎉/㏖. We confirm that the electric conduction mechanism of PVDF thin film is dominated by ionic conduction by investigating the dependence of the leakage current of the thin film on the temperature and the electric field.

• Proceedings of the KIEE Conference
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• 2006.10b
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• pp.171-174
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• 2006

본 연구에서 새로 합성한 적색 도판트 Red-1을 Physical vapor Deposition (PVD) 법을 이용하여 다층구조의 유기 발광 다이오드를 제작하였다. 적층된 유기물 층으로 정공주입층은 4,4',4"-tri [2-naphthyl(phenyl)amino]triphenylamine(2-TNATA) 정공 수송층으로4-4bis [N-(1-napthyl-N-phenyl-amino)biphenyl] (NPB)를 사용하였으며 전자 수송층은 tris (8-quinolinolato)-aluminum ($Alq_3$), 발광층에서의 host 재료로 사용한 물질은 $Alq_3$. 4,4'- N-N'-dicarba zole-biphenyl (CBP), 게스트재료는 Red-1, 정공저지층으로 2,9-dimethyl-4, 7-diphenyl -1 10-phen antroline (BCP), 전자 주입층으로는 lithiumquinolate (Liq)를 사용하여 보다 향상된 전기적, 발광특성을 보이는 소자를 제작하였다. 전하를 주입하는 전극으로 일함수가 큰 투명전극인 ITO (indium-tin-oxide)를 양전극으로, Al을 음전극으로 사용하였다. 그리하여, 발광층 내에서의 host재료 $Alq_3$와 CBP와의 energy transfer의 관점에서 그 특성을 연구하였다.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.15 no.1
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• pp.17-22
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• 2006

Zirconium is widely applied in industrial area. In this study, the exeperiments are performed to investigate the differences in cutting characteristics of zirconium coated material which deposited on cutting tool using physical vapor deposition(PVD). For comparison, TiN coated tool is used to compare with zirconium coated tool. Experimental results were compared for tool wear, surface roughness and cutting force. The tool wear of PVD coated bites is affected by the various cutting conditions. This new stuff 'zirconium coated tool' wears $33\%$ less and improves surface roughness $23\%$ more in various cutting conditions. Cutting force is analyzed by using various workpiece, and the research strongly confirms that 'zirconium' remains better condition than 'titanium'. As a result 'zirconium' coated tool can be performed far better than 'titanium' coated tool on metal cutting.

• Journal of the Korean Vacuum Society
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• v.6 no.S1
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• pp.80-88
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• 1997

The attempt to enhance the strength of materials has been an important subject for materials engineering and scientists. The strength of materials is termed as the ability to support high load without excessive deformation and without breaking catastrophically. The control of dislocation densities and barriers to the movement of dislocations have been considered to be the important methods for the strengthening materials. One of the approaches is mechanical blocking of dislocations by alternately depositing material layers. The typical structure of materials is multilayered and laminated composites. The thickness of each layer is typically in the range of nanometer. Ton avoid confusion with other terminology they may be defined as microlaminate composite materials. The manufacturing process of multilayered laminate structure will be introduced. And the current theoretical theories will be reviewed in view of strengthening of microlaminte composite materials.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.3
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• pp.121-124
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• 2002

CNTs(Carbon Nano Tube) were employed as an electron source in electron-gun of CRT(Cathode-Ray Tube). The CNTs were grown on the Si substrates and the electron gun by LP-CVD(Low Pressure-Chemical Vapor Deposition). Their physical and field emission property satisfied the requirements of the electron gun of CRT. The fabricated electron gun was inserted into 19 inch-sifted CRT and its operating properly was evaluated for practical usage.

• Korean Journal of Materials Research
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• v.13 no.5
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• pp.303-308
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• 2003

Amorphous carbon nitride films deposited on Si(001) substrates by a plasma enhanced chemical vapor deposition (PECVD) technique using CH$_4$and $N_2$as reaction gases were thermally annealed at various temperatures under$ N_2$atmosphere, then their physical properties were investigated particularly as a function of annealing temperature. Above $600^{\circ}C$ a small amount of crystalline $\beta$-$C_3$$N_4$ phase evolves, while the film surface becomes very rough due to agglomeration of fine grains on the surface. As the annealing temperature increases, both the hardness and the $sp^3$ bonding nature are enhanced. In contrast to our expectation, higher annealing temperature results in a relatively higher friction mainly due to big increase in roughness at that temperature.