We demonstrated efficient white light emitting OLEDs with a single emissive layer structure, which was blue-emitting 1,4-bis[2,2-diphenylvinyl]biphenyl (DPVBi) doped with blue luminescent amino-substituted distyrylarylene amine (DSA-amine) and red luminescent [2,6-bis[2-[5-(dibutylamino) phenyl]vinyl]-4H -pyran-4-ylidene]propanedinitrile (DADB). Through the optimization of the device structure, the white light emission with full visible spectral range was obtained. Its CIE color coordinates was (0.32,0.42) at 10 $mA/cm^2$ and the external quantum efficiency, the luminance efficiency and the luminance yield were 3.7 %, 3.3 lm/W and 9.0 cd/A, respectively.

MOCVD(metalorganic chemical vapor deposition)에 의해 성장된 InGaAs/AlGaAs 물질을 이용하여 V-형 양자선 (V-groove quantum-wire) 어레이(array) 구조에서 이득 결합(gain-coupling)에 의한 분포 광귀환(distributed optical feedback) 특성을 조사하였다. 분포 귀환형 (distributed feedback, DFB) 구조를 제작하는 동안 격자 재성장(grating overgrowth)을 피하기 위하여, 새롭게 개발된 constant MOCVD 성장 방법을 적용하였고, Bragg 파장에서 DFB 방향으로 광귀환의 결과인 스펙트럼의 이득 이방성(gain asymmetry)을 실험적으로 관찰하였다.

Organic thin film transistors (OTFTs) are fabricated on the plastic substrate through 4-level mask process without photolithographic patterning to yield the simple fabrication process. And we herewith report for the effect of dielectric surface modification on the electrical characteristics of OTFTs. The KIST-JM-1 as an organic molecule for the surface modification is deposited onto the surface of zirconium oxide $(ZrO_2)$ gate dielectric layer. In this work, we have examined the dependence of electrical performance on the interface surface state of gate dielectric/pentacene, which may be modified by chemical properties in the gate dielectric surface.

In this work, we have used different techniques for the surface passivation: conventional thermal oxidation (CTO), rapid thermal oxidation (RTO), and plasma-enhanced chemical vapour deposition (PECVD). The surface passivation qualities of eight different single and combined double layer have been investigated both on the phosphorus non-diffused p-type FZ silicon and on phosphorus diffused emitter of 100 ${\Omega}/Sq$ and 40 ${\Omega}/Sq$. In the single layer, silicon dioxide $(SiO_2)$ passivates good on the emitter while silicon nitride (SiN) passivates better than on the non-diffused surface. In the double layers, CTO/SiN1 passivates very well both on non-diffused surface on the emitter. However, RTO/SiN1 and RTO/SiN2 stacks are more suitable for surface passivation in solar cells caused by a relatively good passivation qualities and the low optical reflection. Applying these stacks in solar cells we achieved 18.5 % and 18.8 % on 0.5 ${\Omega}$ cm FZ-Si with planar and textured front surface, respectively. The excellent open circuit voltage $(V_{oc})$ of 675.6 mV is obtained the planar cell with RTO/SiN stack.

In this paper, we investigate fringe-field switching (FFS) mode cell by the ion beam (IB) alignment method on the a-C:H thin film, to analyze electro-optical characteristics in this cell. We studied on the suitable inorganic thin film for fringe-field switching (FFS) cell and the aligning capabilities of nematic liquid crystal (NLC) using the new alignment material of a-C:H thin film An excellent voltage-transmittance (V-T) and response time curve of the IB-aligned FFS-LCD was observed with oblique IB exposure on the DLC thin films. Also, AC V-T hysteresis characteristics of the IB-aligned FFS-LCD with IB exposure on the DLC thin films is almost the same as that of the rubbing-aligned FFS cell on a polyimide (PI) surface.

AZO(ZnO:Al) thin film were prepared by FTS(Facing Target Sputtering) system. Change the sputtering conditions, AZO thin film deposited the lower resistivity(<$10-4{\Omega}cm$) so it can use to be a display application electrode. In this study, the electrical and crystallographic effects of target type have been investigated. The crystal structure was studied by XRD and the resistivity of AZO thin film was obtained by the four-point probe.

With varying rapid thermal annealing (RTA) temperature, luminescent properties of ZnMgS:Mn thin film sputter-deposited with one target were measured. Although all samples have the same composition, $Zn_{1-x}Mg_xS:Mn$ (x=0.25) can emit luminescence between 580 and 614 nm, which is controlled by only RTA temperature. It is understood that the energy band gap shift of ZnMgS:Mn thin film phosphor occurs with varying RTA temperature.

We have investigated the photolithographic patterning method of light emitting polymer film for polymer light emitting diodes (PLED). Blue light emitting polymers based on polyfluorene, which can be cured photochemically to yield an insoluble form, have been synthesized using Ni(0) mediated Yamamoto polymerization. The relationship between patterning property and several variables such as the intensity of the exposed UV light, the concentrations of additives, has been studied by using optical microscope analysis, UV/visible spectroscopy, and photoluminescence. We have successfully fabricated PLEDs composed of the patterned emissive layer and their electroluminescence property has been also investigated. In this presentation, the detailed photolithographic patterning method and its application for polymer light emitting display will be discussed.

최근들어, TFT LCD 업체들의 제품 대형화에 따라서 서서히 제품군이 중, 대형 TV를 중심으로 넓은 광시야각 기술 (FFS, IPS, VA)이 적용되고 있으며 고휘도, 고속응답, 고색순도 등 성능향상을 지속하는 가운데 LCD 백라이트로써 LCD TV에 적용하기 위해서는 무엇보다도 현재 기존 제품군보다 높은 휘도 특성의 개선이 요구되고 있다. TV 대응 LCD Panel 은 Monitor 대응 제품에 비해서 일반적으로 해상도가 낮으므로, 투과율면에서 장점은 있으나, 현재의 백라이트 구조로는 만족할만한 성능을 낼 수 없는 상황이다. 그러므로 고휘도 백라이트를 위해서 직하방식 백라이트에 대한 개발 검토가 활발히 이루어지고 있다. 따라서 본 연구에서는 백라이트에서 6500nits를 목표로 직하형 백라이트의 시뮬레이션을 실시하였으며, 램프간 거리, 리플렉터와 램프간 거리, 램프와 확산판간 거리등에 해한 최적화를 통하여 총두께에 따른 특성분석을 실시하였다. 특히, 램프의 수량에 따른 휘도 시뮬레이션을 통해서 백라이트별 기구치수를 결정할 수 있었다. 본 연구에서의 목적인 6500nits의 휘도는 프리즘시트의 적용을 통하여 달성하였다.

The phase transition between amorphous and crystalline states in chalcogenide semiconductor films can controlled by electric pulses or pulsed laser beam; hence some chalcogenide semoconductor films can be applied to electrically write/erase nonvolatile memory devices, where the low conductive amorphous state and the high conductive crystalline stale are assigned to binary states. AST(AsSbTe) used to phase change material by applying electical pulses. Thickness of AST chalcogenide thin film have about 100nm. Electrodes are made of ITO and Al. $T_c$(Crystallization temperature) of AST system is lower than that of the GST(GeSbTe) system, so that the current pulse width of crystallization process can be decreased.

This paper discovers that we form holographic grating in AsGeSeS thin film. Holographic grating is not developed in the length of 10,20,40nm, while it is formed in the thin film of 80nm though it shows very low diffraction efficiency. On the contrary, holographic grating is established in every thin film of Ag(10nm)/AsGeSeS(10,20,40,80nm). Lattice in 10,20 nm thin film builds up, and immediately disappears. In the case of 40nm thin film, even if holographic grating is made up, it seems to have a low diffraction efficiency. Apart from 10,20,40nm, it shows the highest diffraction efficiency in the thin film of 80nm.

Cold cathode fluorescent lamp (CCFL) has been used as a light source for direct type backlights for LCD monitors or TV. One inverter for one CCFL was necessary for maintaining the lamp current so that many inverters were used to drive as many CCFLs of direct type backlight for LCD TV. An inverter for driving 16 CCFLs was developed to reduce the backlight cost. The length and diameter of CCFL were 450mm and 4mm, respectively. Backlight including 16 CCFLs for 26" LCD TV was assembled by using one inverter. The uniformities of the assembled backlight operated by the conventional inverter and the newly developed inverter were 75% and 88%, respectively.

유기발광소자(OLED)Glass/indium-tin-oxide(ITO)/Cu-Pc(copper-phthalocyanine)/N.N'-Bis(3-methylphenyl)-1,1'-biphenylbenzidine/tris-(8-hydroquinoline) aluminum(Alq3)/aluminum(Al)의 기본구조로 제작된 OLED에 다양한 전압을 인가하면서, 마이크로파 근접장 현미경을 이용하여 전압인가에 따른 반사계수(S11)와 소자의 전류-전압특성을 측정함으로써 전기적 전도 특성을 연구하였다. 또한 다양한 인가전압에 따른 EL(electro luminance)를 측정하여 소자의 광학적 특성과 전기적 특성을 연구 비교하였다.

열 증착 방법을 이용하여 copper(II)-phthalocyanine(CuPc) 박막을 glass 기판 위에 제작하였다. 열처리 조건은 $150^{\circ}C$에서 후열(annealing) 처리 하는 방식과 예열하는 두 가지 방식으로 달리하였다. 제작된 박막의 전기전도도를 평가하기 위해 마이크로웨이브 근접장 효과를 이용한 근접장 현미경(near-field scanning microwave microscope)을 이용하여 비파괴적인 방식으로 CuPc 박막의 반사계수(reflection coefficient)를 측정하였다. CuPc 박막의 전기전도도 특성을 UV 흡수도를 통한 에너지 밴드갭의 shift 현상과 관련지어 설명하고 또한 x-ray diffraction(XRD) data를 통해 박막의 결정 특성과 비교하였다. 박막 표면 특성은 SEM(scanning microscope microscopy)을 통해 관측하였다. 열처리 조건에 따른 CuPc 박막의 전기전도도 특성은 후열 처리한 박막의 경우 예열 처리한 박막보다 전기 전도 특성이 향상되었음을 관측할 수 있었다.

저항특성이 다른 ITO박막의 구조특성과 표면특성을 XRD와 AFM(atomic force microscopy), SEM(scanning electron microscopy)을 이용하여 관측하였다. 접촉방식인 4단자 법을 사용하여 ITO박막의 표면전기저항을 측정하였다. 관측된 구조 및 표면특성을 바탕으로 비파괴 비접촉방식을 이용한 근접장 마이크로파 현미경을 이용하여 얻은 ITO박막의 표면저항특성과 비교 연구하였다.

In this work, we have investigated the application of rapid thermal processing (RTP) and plasma enhanced chemical vapour deposition (PECVD) for surface passivation. Rapid thermal oxidation (RTO) has sufficiently low surface recombination velocities (SRV) $S_{eff}$ in spite of a thin oxides and short process time. The effective lifetime is increasing with an increase of the oxide thickness. In the same oxide thickness, The effective lifetime is independent on the process temperature and time. $S_{eff,max}$ is exponentially decreased with increasing oxide thickness. $S_{eff,max}$ can be reduced to 200 cm/s with only 10 nm oxide thickness. On the other hand, three different types of SiN are reviewed. SiN1 layer has a thickness of about 72 nm and a refractive index of 2.8. Also, The SiN1 has a high passivation quality. The effective lifetime and SRV of 1 $\Omega$ cm Float zone (FZ) silicon deposited with SiN1 is about 800 s and under 10 cm/s, respectively. The SiN2 is optimized for the use as an antireflection layer since a refractive index of 2.3. The SiN3 is almost amorphous silicon caused by less contents of N2 from total process. The effective lifetime on the FZ 1 ${\Omega}cm$ is over 1000 ${\mu}s$.

We have studied a liquid crystal (LC) mode (named locked super homeotropic (LSH)) in which the LCs aligned homeotropically are locked by surrounding walls such as cubic, hexagonal and cylinder. In the device, the vertically aligned LCs tilt down symmetrically around the center of the cell when a voltage is applied and thus it exhibits wide viewing angle. The structure of this LSH mode is suitable for large-sized display panels. since the LCs are locked in micro domains the LCs do not flow to the bottom of the panel by gravity. This mode is applicable to achieve high performance TFT-LCD TV because of high performance characteristics such as high contrast, high brightness, wide-viewing angle.

We have studied contrast ratio of a homogeneously aligned nematic liquid crystal (LC) display as a function of the angle between the polarizer axis and LC director. The results show that a cell configuration in which a polarizer axis facing a light source coincides with a short LC axis has a better process margin in terms of high contrast ratio than that of the cell coinciding with a long LC axis.

We have studied electro-optic characteristics of transflective liquid crystal display (LCD) using in-plane switching mode. Unlike previous transflective LCD using a dual gap structure and multi driving circuit, this transflective LCD has a single gap structure and a single driving circuit. In the voltage on state, the electric field is applied horizontally to the LC directors, and then homogeneously aligned LC directors at initial state is rotated to with the electric field. But the twist angle of the LC directors in reflective area is lower than transmissive area. As a result, it is possible to design the transflective LCD with a single gap and a single driving circuit. The transflective display associated with this LC cell exhibits a wide viewing angle in both reflective and transmissive areas.

We have studied an optically compensated splay (OCS) mode driven by fringe electric field. The OCS LC configuration obtained by applying voltage to vertically aligned LCs shows a dark state when an optic axis of the OCS cell coincides with one of crossed polarizer axis. When the fringe electric field is applied, the LC director rotates in plane above whole electrode surface, giving rise to high transmittance and wide viewing angle simultaneously.

본 연구에서는 고휘도 백라이트에 있어서 일반적으로 휘도 향상을 위해서 사용하는 프리즘 혹은 편광프리즘 등의 고가의 기능성 광학시트를 사용하지 않고, 확산시트만을 사용하여 고성능의 BLU 를 제조할 수 있는 핵심부품으로서 프리즘 도광판에 대해서 연구하였다. 고휘도 프리즘 도광판을 구현하는 방법으로 먼저, 광학적으로 시뮬레이션을 통해서 가능성을 검증하고, 기본적인 광학구조의 설계를 수행한 후, 이를 stamper 방식의 사출성형으로 실물을 구현하여 설계의 재현성을 확인하는데 역정을 두었다. 실험결과, 17 inch, 두께 8 mm 사양의 모니터용 도광판에 있어서, 고휘도 BLU를 구현하기 위해서 도광판 밑면과 윗면에 프리즘 구조를 부가한 도광판의 경우에 기존의 인쇄형 도광판보다 약 20%의 휘도향상 효과를 확인할 수 있었으며, 향후 확산시트만을 사용한 고휘도 백라이트로의 응용가능성을 검증할 수 있었다.

We have analyzed the cause of black "mura" and measured it in prism light-guide plate (LGP). Properties of components used in a back light. unit (BLU) have changed by Simulation Tool. We get major factor of black "mura" for improvement in prism LGP. For the improvement of black "mura", removal of brightness "mura" at input light part must precede preferentially because of reflection characteristics of the prism LGP. Removal of brightness "mura" is improved by changing of input light part in LGP and dispersion treatment.

최근 LCD 노트북 제품의 고유한 특정인 경박단소가 요구되면서, 백라이트의 박형화로 인해 광원으로써 램프의 세경화에 대한 개발도 진행되고 있다. 특히, 노트북용 램프의 경우 발열이 심해 도광판을 비롯한 시트류의 주름현상이 발생하며, 수명연장을 위해서 전극의 표면적이 넓거나 일함수(work functuon)가 작은 재질의 개발이 필요하다. 따라서 노트북용으로 저발열, 장수명을 위한 램프를 개발하고 있으며, 본 연구에서도 기존 Ni 전극을 사용한 램프 대비 Nb, Mo, Ta 전극을 사용했을때 통일한 구동조건에서 103%의 휘도특성 개선을 확인할 수 있었고 수명면에서도 기존 Ni 전극 대비 일함수가 낮은 Nb, Mo, Ta 전극을 사용한 램프의 경우 시간경과에 따른 휘도저하가 낮은 것으로 나타났다.

In this study we investigated post ELA(Excimer Laser Annealing) effect on SMC (Silicide Mediated Crystalization) poly-Si (Polycrystalline Silicon) to improve the characteristics of poly-Si. Combining SMC and XeCl ELA were used to crystallize the a-Si (amorphous Silicon) at various ELA energy density for LTPS (Low Temperature Polycrystalline Silicon). We fabricated the conventional SMC poly-Si with no SPC (Solid Phase Crystallization) phase using UV heating method[1] and irradiated excimer laser on SMC poly-Si, so called SMC-ELA poly-Si. After using post ELA we can get better surface morphology than conventional ELA poly-Si and enhance characteristics of SMC poly-Si. We also observed the threshold energy density regime in SMC-ELA poly-Si like conventional ELA poly-Si.

In this study, we report a novel encapsulation method for longevity of an organic thin-film transistor (OTFT) using pentaceneby means of an adhesive multiplayerincluded Al film. For encapsulation of OTFTs, the Al film adhered onto the OTFT in a dry nitrogen atmosphere using a proper adhesive. A lifetime, which was defined as the time necessary to reduce mobility to 2% of initial mobility value, was observed from the typical $I_{D-VD}$ characteristics of the field-effect transistor (FET). The initial field effect mobility ${\mu}$ was measured to be $2.0{\times}10^{-1}\;cm^2/Vs$. The characterization was maintained for long times in air. No substantial degeneration occurred. The performance and the stability are probably due to the encapsulation effect.

The green emitting phosphor, $ZnGa_2O_4:Mn$ thin film with spinel structure were deposited by rf magnetron sputtering. Thin film phosphors were heat-treated in nitrogen, vacuum and air atmosphere, respectively. The effects of the substrates, heat-treatment conditions and the sputtering parameters were investigated. The growing behavior and luminescent properties of thin films depend on the crystallinity of the substrates. The Ga/Zn atomic ratios and luminescent characteristics were dependent on the annealing conditions.

A diode structure of field emission lamps based upon carbon-nanotube is studied. The single-walled carbon nanotubes(SWNTs) were produced by arc discharge method. We made the 1-inch diode type flat lamp using CNTs. We applied anode voltage gradually to refine the field emission behavior of emitter in dynamic vacuum system to study the emission current. the brightness and efficiency, etc. The field emission properties was estimated by varying gaps between the cathode and anode, contents of the glass frit. The good luminous efficiency is showed in the gap $900{\mu}m$, $1200{\mu}m$ and contents of the proper glass frit. For the upper conditions, the luminous efficiencies were respectively 23.30, 11.12 1m/W.

To improvement life-time of the organic light emitting diodes(OLEDs). We investigate the inorganic composite film based on MgO and $SiO_2$ to protect from the moisture and oxygen. The inorganic composite films are added the base materials to the co-operate materials using the mixed process and it is deposited on plastic substrate by e-beam evaporator. In order to analyze as kinds of inorganic materials, Water Vapor method of Transmission Rate (WVTR) and Oxygen Transmission Rate (OTR) are measured by Permatran equipment(MOCON Corp.). For comparison. an MgD- and $SiO_2$-based composite film has lower values of WVTR and OTR than inorganic composite/compound films of ones. The results obtained here shows that this film is suitable for passivation layer to extend the life-time of OLEDs.

The organic light emitting diode (OLED) is proposed as the novel source in the microchip because it has ideal merits (various wavelengths, thin-film structure and overall emitting) for the integration. In this paper, we fabricated the finger-type pin photodiodes for fluorescence detection and the advanced microchip with OLED integrated pn the microchannel. The finger-type in the diode design extended the depletion region and reduced the internal resistance about 31.2% than rectangular-type. The photodiodes had a 100pA leakage current and a 8720 sensitivity $(I_{Light}/I_{Dark})$ at -1 V bias. The interference filter with 32 layers ($SiO_2$, $TiO_2$) was directly deposited on the photodiode. The OLED was fabricated on the ITO coated glass and was bonded with LOC. The application of thin-film OLED increased the excitation efficiency and simplified the integration process extremely. The prototype device of this application had a superior sensitivity of 100nM-LOD in the fluorescence detection.

We studied the nematic liquid crystal (NLC) aligning capabilities using the new alignment material of a SiO thin film. The homogenous alignment can be obtain어 using ion beam (IB) exposure on the SIO thin film, when positive type NLC ($Delta\varepsilon$>0) was injected However, the homeotropic alignment can be obtained using ion beam (IB) exposure on the SiO thin film, when negative type NLC ($\Delta\varepsilon$>0) was injected The LC aligning ability on the SiO thin film depends on the dielectric anisotropy type of LC. It will be discussed.

We investigated the electro-optical(EO) performances of the super twisted nematic liquid crystal display(STN-LCD) on the polyimide(PI) surface using polymer film. The NLC pretilt angles generated are about $18^{\circ}$ by the rubbing alignment method on thin plastic substrates. However, the pretilt angle are at about $13^{\circ}$ lower on the glass substrate than on thin plastic substrate. Monodomain alignment of the plastic STN-LCD can be observed. A stable voltage-transmittance(V-T) curve of the plastic STN-LCD was observed on the polyimide(PI) surfaces using polymer film. Also, a faster response time for the plastic STN-LCD on the polyimide(PI) surfaces using polymer film can be achieved.

We investigated response characteristics of liquid crystal display(LCD) with different operating mode of nematic liquid crystals (NLCs) such as $45^{\circ}$twist nematic (TN), $67.3^{\circ}$TN and ECB(electrical controlled birefringence) on a rubbed polyimide (PI) surface. The three kinds of LCD operating mode obtain stable EO performance. Low transmittances of the $45^{\circ}$TN and $67.3^{\circ}$TN cell on the rubbed PI surface were achieved by using low cell gap d. The fast response time of ECB cell among the three kinds of LCD operating mode was measured.

We synthesized photoalignment material of high thermal resistance with hydroxyl aromatic polyimide, and studied the liquid crystal (LC) aligning capabilities on the photopolymer layers. Also, electro-optical (EO) performances for the twisted-nematic (TN)-liquid crystal display (LCD) photoaligned with linearly polarized UV exposure were investigated. A good LC alignment with UV exposure on the photopolymer surface can be obtained. However, the low pretilt angles were obtained below $1^{\circ}$. The Voltage-transmittance (V-T) curve without backflow bounce in the photoaligned TN cell with UV exposure was observed. The response time of photoaligned TN cell was measured about 24 ms. Finally, The photoaligned TN cell has few hysteresis, and shows the residual DC voltage that is less.

현재 PDP는 차세대 대형 평판 표시장치로서 각광을 받고 있으며 빠른 속도로 개발이 진행되고 있다. AC PDP에서 가장 큰 문제는 위도 및 방전효율의 향상과 전력손실의 저감, 높은 contrast의 실현, 제품 가격의 저하 등에 관한 문제이다. 본 연구에서는 벽전압 전달곡선을 이용한 방전 동작 특성에 대해 고찰하고자 한다. 방전 유지전압 주파수가 변화할 때 방전 개시전압이 감소하나 메모리 마진은 거의 동일함을 보였다. Duty 비를 변화시키면 방전개시전압은 감소하는 경향이 있지만 방전유지전압은 거의 일정하였다.