• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.703-706
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• 2004

This paper deals with the various sealing conditions in a vacuum and the discharge characteristics. The MgO thin film is prepared by e-beam evaporation method. Sealing process was performed in a vacuum at panel temperature of 430 $^{\circ}C$. We find the cracks on the MgO film surface, which results in higher discharge voltage and lower luminous efficiency. The vacuum in-line sealing technology does not require additional annealing process but induces the MgO cracks because of the high temperature sealing cycle in a vacuum. Therefore we modify the vacuum in-line sealing cycle which the MgO cracks are not found and the good characteristics of plasma displays are found in higher sealing pressure at sealing temperature of 430 $^{\circ}C$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.11a
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• pp.101-104
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• 1998

A new planar-type micro gas sensor was designed and fabricated on silicon substrate and the operating characteristics of the sensor were investigated. The thin sensitive film of the sensor was fabricated by spin-coating of the SnO$_2$ sol solution which was synthesized by hydrothermal method. The spin-coating method for preparation of sensing layer was adopted to improve the long-term stability of the fabricated sensing film instead of physical methods such as rf sputtering and thermal evaporation. The fabricated microsensor showed a fairly good sensing performance for CO gas in air at 250$^{\circ}C$ The sensitivity(S=Ra/Rg) was shown to be about 5 to 2000ppm CO with heating power of 50mW.

• Proceedings of the KIEE Conference
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• 1998.11c
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• pp.792-794
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• 1998

The TPD and the $Alq_3$ film are widely used as a hole transport layer and an emitter layer respectively, in organic electroluminescent(EL) device (ITO Glass/TPD/$Alq_3$/metal). In this structure, we fabricated two models. Model(1) having ITO glass/$Alq_3$/Al structure and model(2) having ITO Glass/TPD/$Alq_3$/Al structure were fabricated by the vacuum evaporation. The comparison between model(1) and model(2) was made about the absorbance, the wave length, the current-voltage characteristic and the ln I - $V^{(1/2)}$characteristic respectively. Electroluminescence of green and wavelength of 510[nm] were observed in both model. We observed absorbance from 320[nm] to 430[nm] in $Alq_3$ material and from 250[nm] to 400[nm] in TPD material.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.334-334
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• 2011

We applied N-ion bombardment and heat treatment to the Cu thin films deposited on aluminum oxide layer for the enhancement of adhesion. With e-beam evaporation method. $1,000{\AA}$ thick Cu pre-bombardment layer was deposited on the aluminum oxide surface and then N-ion beam was bombared in order to mix the atoms at the film/substrate interface. Additional $4,000{\AA}$-thick Cu film was the coated. Subsequently, the ion mixide Cu on aluminum oxide was annealed at $200^{\circ}C$ and $300^{\circ}C$ in vacuum.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.314-316
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• 2006

In this paper, the plastic organic thin-film transistors (OTFTs) with $32{\ast}32$ array are presented. Flexible organic light emitting diodes (OLEDs) operated by OTFTs are fabricated with a novel lamination method and the results are also presented. OTFT pixels defined by photolithography, and pentacene deposited by thermal evaporation. Fabrication method and the performances of green PHOLEDs with high efficiency, stability, and electrical performance are discussed.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.361-361
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• 2011

Cu(InGa)(SeS2) (CIGS) thin film solar cells have recently reached an efficiency of 20%. Recent studies suggest a double graded band gap structure of the CIGS absorber layer to be a key issue in the production of high efficiency thin film solar cell using by sputtering process method. In this study, Cu(InGa)(SeS2) absorbers were manufactured by selenization and surfulization, we have deposited CIG precusor by sputtering and Se layer by evaporation before selenization. The objective of this study is to find out surfulization effects to improve Voc and to compare with non-surfulization Cu(InGa)Se2 absorbers. Even if we didn't analysis Ga depth profile of Cu(InGa)(SeS2) absorbers, we confirmed increasing of Eg and Voc through surlization process. In non-surfulization Cu(InGa)Se2 absorbers, Eg and Voc are 0.96eV and 0.48V. Whereas Eg and Voc of Cu(InGa)(SeS2) absorbers are 1.16eV and 0.57V. And the efficiency of 9.58% was achieved on 0.57cm2 sized SLG substrate. In this study, we will be discussed to improve Eg and Voc through surfulization and the other method without H2S. gas.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.2
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• pp.102-107
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• 2003

This study puts focus on the optimization of growth temperature of CIGS absorber layer which affects severely the performance of solar cells. The CIGS absorber layers were prepared by three-stage co-evaporation of metal elements in the order of In-Ga-Se. The effect of the growth temperature of 1st stage was found not to be so important, and 350$^{\circ}C$ to be the lowest optimum temperature. In the case of growth temperature at 2nd/3rd stage, the optimum temperature was revealed to be 550$^{\circ}C$. The XRD results of CIGS films showed a strong (112) preferred orientation and the Raman spectra of CIGS films showed only the Al mode peak at 173cm$\^$-1/. Scanning electron microscopy results revealed very small grains at 2nd/3rd stage growth temperature of 480$^{\circ}C$. At higher temperatures, the grain size increased together with a reduction in the number of the voids. The optimization of experimental parameters above mentioned, through the repeated fabrication and characterization of unit layers and devices, led to the highest conversion efficiency of 15.4% from CIGS-based thin film solar cell with a structure of Al/ZnO/CdS/CIGS/Mo/glass.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.347-347
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• 2012

Nickel Oxide (NiO) is a transition metal oxide of the rock salt structure that has a wide band gap of 3.5 eV. It has a variety of specialized applications due to its excellent chemical stability, optical, electrical and magnetic properties. In this study, we concentrated on the application of NiO thin film for transparent conducting oxide. The energy band structure, electronic and optical properties of Nickel Oxide (NiO) thin films grown on Si by using electron beam evaporation were investigated by X-Ray Photoelectron Spectroscopy (XPS), Reflection Electron Energy Loss Spectroscopy (REELS), and UV-Spectrometer. The band gap of NiO thin films determined by REELS spectra was 3.53 eV for the primary energies of 1.5 keV. The valence-band offset (VBO) of NiO thin films investigated by XPS was 3.88 eV and the conduction-band offset (CBO) was 1.59 eV. The UV-spectra analysis showed that the optical transmittance of the NiO thin film was 84% in the visible light region within an error of ${\pm}1%$ and the optical band gap for indirect band gap was 3.53 eV which is well agreement with estimated by REELS. The dielectric function was determined using the REELS spectra in conjunction with the Quantitative Analysis of Electron Energy Loss Spectra (QUEELS)-${\varepsilon}({\kappa},{\omega})$-REELS software. The Energy Loss Function (ELF) appeared at 4.8, 8.2, 22.5, 38.6, and 67.0 eV. The results are in good agreement with the previous study [1]. The transmission coefficient of NiO thin films calculated by QUEELS-REELS was 85% in the visible region, we confirmed that the optical transmittance values obtained with UV-Spectrometer is the same as that of estimated from QUEELS-${\varepsilon}({\kappa},{\omega})$-REELS within uncertainty. The inelastic mean free path (IMFP) estimated from QUEELS-${\varepsilon}({\kappa},{\omega})$-REELS is consistent with the IMFP values determined by the Tanuma-Powell Penn (TPP2M) formula [2]. Our results showed that the IMFP of NiO thin films was increased with increasing primary energies. The quantitative analysis of REELS provides us with a straightforward way to determine the electronic and optical properties of transparent thin film materials.

• Journal of the Korean institute of surface engineering
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• v.46 no.3
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• pp.116-119
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• 2013

To improve the corrosion resistance of an electrogalvanized steel sheet, we deposited magnesium film on it using a vacuum evaporation method and annealed the films at $250-330^{\circ}C$. The zinc-magnesium alloy is consequently formed by diffusion of magnesium into the zinc coating. From the anodic polarization test in 3% NaCl solution, the films annealed at $270-310^{\circ}C$ showed better corrosion resistance than others. In X-ray diffraction analysis, $ZnMg_2$ was detected through out the temperature range, whereas $Mg_2Zn_{11}$ and $FeZn_{13}$ were detected only in the film annealed at $310^{\circ}C$. The depth composition profile showed that the compositions of Mg at $270-290^{\circ}C$ are evenly and deeply distributed in the film surface layer. These results demonstrate that $270-290^{\circ}C$ is a proper temperature range to produce a layer of $MgZn_2$ intermetallic compound to act as a homogeneous passive layer.

• Journal of the Korean institute of surface engineering
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• v.29 no.6
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• pp.788-796
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• 1996

$TiO_2$ films prepared by RF magnetron sputtering, electron beam evaporation, ion assisted deposition (IAD) and sol-gel method are prepared on c-Si substrate and vitreous silica substrate respectively. From the transmission spectra of $TiO_2$ films on vitreous silica substrate in the spectral region from 190 nm to 900 nm, k($\lambda$) of $TiO_2$ is obtained. Using k($\lambda$) in the interband transition region the coefficients of the quantum mechanical dispersion relation of an amorphous $TiO_2$ and hence n($\lambda$) including the optically opaque region of above fundamental transition energy are obtained. The spectroscopic ellipsometry spectra of $TiO_2$ films in the spectral region of 1.5-5.0eV are model analyzed to get the film packing density variation versus i) substrate material, ii) film thickness and iii) film growth technique. The complex refractive index change of these $TiO_2$ films versus water condensation is also studied. Film micro-structures by SE modelling results are compared with those by atomic force microscopy images and X-ray diffraction data.