• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.174-176
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• 2000

We have synthesized the new blue electroluminescent material, Bis(3-N-ethylcarbazolyl)cyanoisophthalidene(BECCIP), and characterized its properties by UV/visible absorption, photoluminescent(PL) and electroluminecent(EL) spectrum. This material is well vacuum-deposited far thin film and has clear surfaced thin film property. The BECCIP shows blue PL and EL spectra at around at 485nm.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.11a
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• pp.163-166
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• 1997

Electroluminescent(EL) dcvice based on organic thin layers have attracted lots of interests because of thier possible application as large-area light-emitting displays. It was known that MEH-PPV and 1, 1, 4, 4, -Tetraphenyl-1, 3-butadiene(TPB) has red and blue emission peak at 580nm and 480nm, respectively. In this study, MEH-PPV films and TPB films were prepared by spin coating and vacuum deposition method, respectively. Films of MEH-PPV and TPB double layer were also prepared by the same method. Photoluminescent(PL) characteristics of these single and doubler layers were investigated, where a cell structure of glass substrate/ITO/MEH-PPV and/or TPB/Al was employed. It was found that the photoluminescent efficiency of TPB film was higher than that of MEH-PPV film with a single layer and also with a double structure. These films have also different I-V characteristics.

• Korean Journal of Materials Research
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• v.11 no.6
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• pp.448-452
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• 2001

The ZnS:Cu,Cl thick film electroluminescent devices with the stacking type(separated with phosphors and insulator layers) and the composite type (mixed with phosphor and insulator materials) emission layers were fabricated on ITO/glass substrates by the screen printing methods. The opical and electrical properties were investigated as fundations of applied voltages and frequencies. In the stacking type, the luminance was about 58 cd/$\m^2$ at the applied voltage of 400Hz, 200V and increased to 420 cd/$\m^2$ with increasing the frequency to 30Hz. For the composite type devices, the threshold voltage was 45V and the maximum luminance was 670 cd/$\m^2$ at the driving condition of 200V, 30Hz. The value of luminance of the composite type device showed 1.5 times higher than that of stacking type device. The main emission peak was 512 nm of bluish-green color at 1Hz frequency below and shifted to 452 nm in the driving frequency over 5Hz showing the blue omission color. There were no distinct differences of the main emission peaks and color coordinate for both samples.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.1091-1094
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• 2004

High-luminous efficiency full-color emissions in photoluminescence (PL) were obtained in $GdVO_4$ phosphor thin films co-doped with various amounts of Eu, Er and/or Tm and postannealed at approximately 1000$^{\circ}C$. The $GdVO_4$:Eu,Er,Tm phosphor thin films were deposited on thick $BaTiO_3$ ceramic sheets by r.f. magnetron sputtering using powder targets and postannealed in an air atmosphere. The rare earth (RE) content (RE/(Gd+V+RE) atomic ratio) in the oxide phosphor thin films was varied in the range from 0.1 to 2 at.%. It was found that the excitation of $GdVO_4$:Eu.Er,Tm thin films is attributed to band-to-band transition. A white PL emission was obtained in a $GdVO_4$:Eu,Er,Tm thin film with Eu, Er and Tm contents of 0.2, 0.7 and 1 at.%, respectively: CIE chromaticity color coordinates. (X=0.352 and Y=0.351). In addition, a white emission was obtained in a thin-film electroluminescent (TFEL) device made with this thin film.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.04b
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• pp.137-140
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• 2004

We treated $O_2$ plasma on ITO thin film using RIE (Reactive Ion Etching) system, and analyzed the ingredient of ITO thin film according to change of processing conditions. The ingredient analysis of ITO thin film was used by EDS (Energy Dispersive Spectroscopy) and XPS (X-ray Photoelectron Spectroscopy) to compare and analyze the ingredient of bulk and surface. We measured electrical resistivity using Four-Point-Probe and calculated sheet resistance, and ITO surface roughness was measured by using AFM (Atomic Force Microscope). Finally, we fabricated OLEDs (Organic Light-Emitting Diodes) device using substrate that was treated optimum ITO surface. The result of the study for electrical and optical properties using I V L System (Flat Panel Display Analysis System), we confirmed that electrical properties (I-V) and optical properties (L-V) were improved.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.95-95
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• 2014

An OLED(Organic Light-Emitting Diode) device based on the emissive electroluminescent layer a film of organic materials. OLED is used for many electronic devices such as TV, mobile phones, handheld games consoles. ULVAC's mass production systems are indispensable to the manufacturing of OLED device. ULVAC is a manufacturer and worldwide supplier of equipment and vacuum systems for the OLED, LCD, Semiconductor, Electronics, Optical device and related high technology industries. The SMD Series are single-substrate sputtering systems for deposition of films such as metal films and TCO (Transparent Conductive Oxide) films. ULVAC has delivered a large number of these systems not only Organic Evaporating systems but also LTPS CVD systems. The most important technology of thin-film encapsulation (TFE) is preventing moisture($H_2O$) and oxygen permeation into flexible OLED devices. As a polymer substrate does not offer the same barrier performance as glass substrate, the TFE should be developed on both the bottom and top side of the device layers for sufficient lifetimes. This report provides a review of promising thin-film barrier technologies as well as the WVTR(Water Vapor Transmission Rate) properties. Multilayer thin-film deposition technology of organic and inorganic layer is very effective method for increasing barrier performance of OLED device. Gases and water in the organic evaporating system is having a strong influence as impurities to OLED device. CRYO pump is one of the very useful vacuum components to reduce above impurities. There for CRYO pump is faster than conventional TMP exhaust velocity of gases and water. So, we suggest new method to make a good vacuum condition which is CRYO Trap addition on OLED evaporator. Alignment accuracy is one of the key technologies to perform high resolution OLED device. In order to reduce vibration characteristic of CRYO pump, ULVAC has developed low vibration CRYO pumps to achieve high resolution alignment performance between Metal mask and substrate. This report also includes ULVAC's approach for these issues.

• Journal of the Korean Ceramic Society
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• v.32 no.7
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• pp.761-768
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• 1995

Double layered BaTiO3 thin films with high dielectric constant as well as good insulating property were prepared for the application to low voltage driving thin film electroluminescent (TFEL) device. BaTiO3 thin films were formed by rf-magnetron sputtering technique. Amorphous and polycrystalline BaTiO3 thin films were deposited at the substrate temperatures of room temperature and 55$0^{\circ}C$, respectively. Two kinds of films prepared under these conditions showed high resistivity and high dielectric constant. The figure of merit (=$\varepsilon$r$\times$Eb.d) of polycrystalline BaTiO3 thin film was very high (8.43$\mu$C/$\textrm{cm}^2$). The polycrystalline BaTiO3 showed a substantial amount of leakage current (I), under the high electric field above 0.5 MV/cm. The double layered BaTiO3 thin film, i.e., amorphous BaTiO3 layer coated polycrystalline BaTiO3 thin film, was prepared by the new stacking method and showed very good dielectric and insulating properties. It showed a high dielectric constant fo 95 and leakage current density of 25 nA/$\textrm{cm}^2$ (0.3MV/cm) with the figure of merit of 20$\mu$C/$\textrm{cm}^2$. The leakage current density in the double layered BaTiO3 was much smaller than that in polycrystalline BaTiO3 under the high electric field. The saturated brightness of the devices using double layered BaTiO3 was about 220cd/$m^2$. Threshold voltage of TFEL devices fabricated on double layered BaTiO3 decreased by 50V compared to the EL devices fabricated on amorphous BaTiO3.

• Proceedings of the Materials Research Society of Korea Conference
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• 1994.11a
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• pp.79-80
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• 1994

A systematic study on isoelectronic impurities in thin-film eletroluminescent devices (TFELD) has been made on the basis of the experimental analysis aimed at a survey for the blue-emitting materials. Codoping effects of isoelectronic impurities, such as oxygen(O), tellurium(Te), and lithium(Li), on the emissive characteristics of ZnS:Ce$^{3+}$ and ZnS:Tm$^{3+}$TFELD have been investigated by means of the X-ray diffraction studies, the Auger electron spectroscopy, the cathodoluminescent spectra, and the electroluminescent spectra. Experiment results reveal that oxygen codoping gives rise to an increase of the luminance, due to a suppression of the nonradiative energy transfer via sulfur vacancies Te codoping in ZnS:Ce$^{3+}$ TFELD result in a large change in the crystal field around Ce$^{3+}$ ions. Li codoping in ZnS:Tm$^{3+}$ TFELD causes the luminance to increase slightly, due to a lowering in the symmetry of Tm$^{3+}$ions. Likewise, the experimental results suggest strongly that an Auger-type enegy loss via lattece defects such an sulfur vacancies acts as a non-emissive in TFELD.ve in TFELD.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1054-1058
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• 2006

We report the synthesis and electroluminescent properties of new aromatic compounds as hole-transporting materials based on phenothiazine, such as 1,4-diphenothiazyl-benzene [DPtzB], 1,4-diphenothiazyl-xylene [DPtzX] and 9,10-diphenothiazyl-anthracene [DPtzA]. DPtzB thin film exhibited photoluminescence (PL) maximum emission peak and emission shoulder at 450 and 475nm, and maximum emission at 447nm without emission shoulder was found in DPtzX thin film. When DPtzA was excited by incident light of 359nm, DPtzA showed strong PL emission at 417nm and weak emission at 600nm. Luminance efficiency of DPtzB, DPtzX and DPtzA-based electroluminescence (EL) devices was 3.57, 3.46 and 0.47cd/A, and power efficiency of DPtzB, DPtzX and DPtzA-based EL devices was 1.48, 1.26 and 0.20lm/W.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.8
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• pp.679-687
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• 2001

It is known that amorphous BaTiO$_3$ thin films have good insulating properties[1][2]. In this investigation, amorphous BaTiO$_3$ thin films were deposited by rf magnetron sputtering on thick BaTiO$_3$ films of AC powder EL devices which were fabricated by screen-printing. The electrical and optical properties of the EL devices were then investigated. Adding amorphous BaTiO$_3$ thin film, it showed that leakage current density was decreased. Especially, leakage current density was decreased more with he sample of 0.5-hour deposition than the sample of 4-hours deposition. This result led to the improvement of luminous efficiency by 11%. It could be concluded that proper amorphous BaTiO$_3$ thin film deposition improved the surface property of dielectric layer.