• Journal of Magnetics
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• v.17 no.4
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• pp.261-264
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• 2012

Interfacial properties of 5 nm MgO(001)/7 nm Fe(001)/1.8 nm MgO(001)/t nm Cu-phthalocyanine (CuPc) hybrid multilayers with t = 0, 1, 7, and 10 were investigated by using x-ray photoemission spectroscopy (XPS). Rather sharp interfacial properties were observed in the CuPc films grown on an epitaxial MgO/Fe/MgO(001) trilayer than a MgO/Fe(001) bilayer. This work suggests a new way to improve device performance of organic spintronic devices by utilizing an artificially grown MgO(001) thin layer.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.18 no.2
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• pp.72-75
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• 2008

Zinc oxide (ZnO) thin films were prepared by a sol-gel method. The structural and electrical properties were investigated by varying drying and annealing temperatures. The thin films were coated (250 nm) by spin-coating method on glass substrates. The optimum drying temperature of ZnO thin films was 300$^{\circ}C$ where the resistivity was the lowest and the preferred c-axis orientation was the highest. The annealing was carried out in air and inert atmospheric conditions. The degree of the preferred c-axis orientation was estimated. The highest preferred c-axis orientation was recorded at 600$^{\circ}C$. The preferred c-axis orientation and grain growth resulted in the mobility enhancement of the ZnO thin films, and the lowest resistivity was 0.62${\Omega}{\cdot}cm$ at 600$^{\circ}C$.

• Proceedings of the Korean Vacuum Society Conference
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• 2005.08a
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• pp.67-67
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• 2005

• Journal of Surface Science and Engineering
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• v.29 no.5
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• pp.505-511
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• 1996

The field emission characteristics of diamond films deposited by microwave plasma enhanced chemical vapor deposition (MPECVD) method were investigated. Diamond films were deposited on n-type Si(100) wafer using various mixtures of hydrogen and methane gas, and the I-V characteristics are measured. We observed that the field emission characteristics depend on the $CH_4$ concentration and the diamond film thickness. All the films show remarkable emission characteristics; low turn-on voltage, high emission current density at lower voltage, uniform stable current density, and good stability and reproducibility. The threshold field for producing a current density of 1mA/$\textrm{cm}^2$ is found as low as 7.6V/$\mu\textrm{m}$.

• Journal of the Korean Vacuum Society
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• v.7 no.s1
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• pp.30-36
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• 1998

The plasma-spray technique is currently the most frequently used method to produce calcium phosphate coatings. Hydroxyapatite(HAp), one form of calcium phosphate, is preferred by its ability to form a direct bond with living bone, resulting in improvements of implant fixation and faster bone healing. Recently, concerns have been raised regarding the viable use and long-term stability of plasma-spray HAp coatings due to its nature of comparatively thick, porous, and poor bonding strength to metal implants. Thin layers (maximum of few microns) of calcium phosphate were formed by an e-beam evaporation with and without ion bombardments. The Ca/P ration of film was controlled by either using the evaporants having the different ration of Ca/P with addition of CaO, or adjusting the ion beam assist current. The Ca/P ration had great effects on the structure formation after heat treatment and the dissolution bahavior. The calcium phosphate films produced by IBAD exhibited high adhesion strength.

• Applied Chemistry for Engineering
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• v.16 no.1
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• pp.112-116
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• 2005

We investigated the surface modification method for the preparation of organic-inorganic hybrid composite thin film. Gelatin obtained from the decomposition of collagen was allowed to adsorb in a polystyrene tissue culture dish for 2 h to from layers of gelatin. Supersaturated ionic solution of calcium and phosphorus was injected on the gelatin adsorbed layer to form calcium phosphate thin film. During the initial period of incubation, nucleates were formed. With increase of the incubation time, CaP (calcium phosphate) thin film grew on the surface of the culture dish. The gelatin/CaP thin film displayed the highly porous three-dimensional surface structure. Attenuated, total reflectance Fourier transform, infra-red spectroscopy (ATR-FTIR) was used to analyze the chemical properties of CaP film. The analysis demonstrated that the CaP film formed at initial period of treatment appeared to be amorphous. With increase of incubation time, the crystallinity of the film was slightly increased, but the presence of the peaks for the low crystalline CaP confirmed that the CaP thin film prepared in this study was poorly crystallized.

• The Journal of Korean Academy of Prosthodontics
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• v.32 no.2
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• pp.212-224
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• 1994

The purpose of this study was to evaluate and compare film thickness of five kinds of resin luting cements [Comspan, Panavia Ex, Maryland bridge adhesive, All-bond C & B cementation kit, and Super-bond C & B]. Zinc-phosphate cement and glass-ionomer cement were used as the control group. In order to measure the film thickness the methods used were in broad compliance with ADA Specification No. 8, a tapered-die system that simulates clinical conditions more closely, and the connected tapered-die system that simulates bridge conditions. The inorganic filler size of resin cements was also examined with scanning electron micrographs. The results were obtained as follows ; 1. The film thickness of resin cements was increased in the order of Comspan, Panavia Ex, Super-bond C & B, Maryland bridge adhesive, and All-bond C & B cementation kit. Maryland bridge adhesive and All-bond C & B cementation kit showed significantly higher film thickness than the control group(p<0.01). 2. For all resin cements, there was a significant difference of film thickness between the ADA method and the tapered-die system. Generally, the tapered-die system demonstrated lower film thickness than the ADA method(p<0.01). 3. There was no significant difference in film thickness between the tapered-die system and the tapered-die bridge system in all resin cements(p<0.01). 4. The scanning electron microscope showed that the cement with larger filler had a tendency to be higher in film thickness.

• Transactions on Electrical and Electronic Materials
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• v.13 no.2
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• pp.93-97
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• 2012

In this study, the fabrication and the characteristic analyses of OLED using in-situ passivation are investigated. OLEDs represent a disadvantage in decreasing its life due to the degradation caused by the penetration of moisture and oxygen. After the fabrication of OLED, an in-situ passivation method for inorganic thin films is developed. A process that uses PECVD method which can apply a vapor deposition process at room temperature is also developed. Changes in the degradation and electric characteristics of OLEDs are also analyzed by applying $SiO_2$ and SiNx thin films to OLED as a passivation layer. By applying the fabricated thin film to OLEDs as a passivation layer, the moisture penetration in a single layer film is ensured below $1{\times}10^{-2}\;g/m^2.day$. This leads to the improvement of such degradation characteristics in the application of multilayer films.

• Progress in Superconductivity and Cryogenics
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• v.5 no.2
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• pp.41-45
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• 2003

Resistance distribution in thin film type SFCL elements of different shunt layer thickness was investigated. The 300 nm thick film of 2 inch diameter was coated with a gold layer and patterned into 2 mm wide meander lines. The shunt layer thickness was varied by ion milling the shunt layer with Ar ions, and also by having the shunt layer grown in different thickness. The SFCL element was subjected to simulated AC fault current for measurements. It was immersed in liquid nitrogenduring the experiment. The resistance distribution was not affected by the shunt layer thickness at applied voltages that brought the temperature of the elements to similar values. This result could be explained with the concept of heat transfer from the film to the surroundings. The resistance distribution was independent of the shunt layer thickness because thick sapphire substrates of high thermal conductivity dominated the thermal conductance of the elements.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.234.2-234.2
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• 2014

Organic light emitting diode (OLED) is considered as the next generation flat panel displays due to its advantages of low power consumption, fast response time, broad viewing angle and flexibility. For the flexible application, it is essential to develop thin film encapsulation (TFE) to protect oxidation of organic materials from oxidative species such as oxygen and water vapor [1]. In many TFE research, the inorganic film by atomic layer deposition (ALD) process demonstrated a good barrier property. However, extremely low throughput of ALD process is considered as a major weakness for industrial application. Recently, there has been developed a high throughput ALD, called 'spatial ALD' [2]. In spatial ALD, the precursors and reactant gases are supplied continuously in same chamber, but they are separated physically using a purge gas streams to prevent mixing of the precursors and reactant gases. In this study, the $Al_2O_3$ thin film was deposited by spatial ALD process. We characterized various process variables in the spatial ALD such as temperature, scanning speed, and chemical compositions. Water vapor transmission rate (WVTR) was determined by calcium resistance test and less than $10-^3g/m^2{\cdot}day$ was achieved. The samples were analyzed by x-ray photoelectron spectroscopy (XPS) and field emission scanning electron microscope (FE-SEM).