• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.7
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• pp.600-604
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• 2005

We studied that structural and optical properties of ZnO films depend on oxygen contents. ZnO films were deposited on Si (111) substrates at room temperature by rf sputtering system and the thickness of films was 100 nm. The ZnO films were annealed in thermal furnace for 2 h at 800 and $900^{\circ}C$ in $H_2O,\;N_2$, and air ambient gases to control oxygen contents. We used AES, PL, XRD, AFM. As our result, crystal quality and luminescence improved until O/Zn is 1. However, when O/Zn ratio Is larger than 1, the structural and optical properties were getting worse.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1134-1135
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• 2015

In this paper, we reported fabrication of sealing the glass substrate using laser treatment at low temperature for electrochemical luminescence (ECL) cell. The laser treatment at temperature is using laser diode. The glass substrate sealing by laser treatment tested at 1-5 W, 1-5 mm/s for builted and tested. The sealing laser treatment method will allow associate coordination between the two glass substrate was enclosed. The effect of laser treatment to sealing the glass substrate was found to have cracks and air gap at best thickness of about $845-780{\mu}m$ for condition 5 W, 1-5 mm/s. The surface of sealing was roughness which was not influent to electrodes So, it is more effective viscosity between two glasses substrate.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.788-791
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• 2002

The phosphors of high luminous efficiency for PDP application must have high purity, single phase, and dense surface. In this work, the polymeric reaction was applied to preparation of spherical phosphor by aerosol pyrolysis in order to enhance mechanical and optical characteristics. The red phosphor of (Y,Gd)$BO_3$:Eu was prepared from polymeric precursor, in which citric acid and ethylene glycol were used as ion carriers, i.e monomers. For enhancing the luminescence intensity and mechanical characteristics. optimum synthesizing condition were investigated through concentration of monomers, synthetic temperature. doped activator concentrations, and annealing process. The phosphors synthesized with monomers showed quite different morphology from those without monomers. It was observed that polymeric precursor made an effect on particle formation mechanism and status of particles surface. The resultant spherical phosphors show the comparable luminescent properties to the commercial product (product by Nichia co.). Also, they were observed to have the rigid surface.

• Transactions on Electrical and Electronic Materials
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• v.5 no.5
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• pp.173-179
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• 2004

The influence of heavily Si impurity doping in the GaN barrier of InGaN/GaN multi-quantum well structures of blue light emitting diodes were investigated by growing samples in metal-organic chemical vapor deposition. The delta-doped sample was compared to the sample with the undoped barrier. The delta-doped sample shows the tunneling behavior and forms the energy level of 0.32 eV for tunneling and the photoemission of the 450-nm band. The photo-luminescence shows the blue-shifted broad band of the radiative transition due to the inclusion of Si delta-doped layer indicating that the delta doping effect acts to form the higher energy level than that of quantum well. The dislocation may provide the carrier tunneling channel and plays as a source of acceptor. During the tunneling of hot carrier, there was no light emission.

• Journal of the Korean Ceramic Society
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• v.37 no.9
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• pp.927-932
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• 2000

Mg(NO$_3$)$_2$가 용해된 IPA 용액에서 형광 분말의 전기영동법에 의한 증착 과정을 증착 시간, Mg(NO$_3$)$_2$의 농도 및 열처리 조건에 따라 분석하였다. 전기영동법으로 가장 두께가 균일한 형광막을 얻기 위한 Mg(NO$_3$)$_2$의 최적 농도는 $10^{-3}$~$10^{-4}$ M였다. 형광체의 접착력을 향상시키기 위해 새로운 방법을 고안하였다. 즉 전기영동법으로 증착된 형광막에 B$_2$O$_3$가 용해된 IPA 용액을 분사한 후 열처리를 하였다. 그 결과 기존의 PL 특성을 그대로 유지하면서 접착력을 향상시킬 수 있었다. 그러나 CL 휘도는 약간 감소하였다.

• Journal of Integrative Natural Science
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• v.1 no.1
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• pp.32-35
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• 2008

We fabricated surface pattern on a light guide panel (LGP) using $CO_2$ laser to improve the luminescence performance of inner-scatterer LGP, which is made of PMMA sample with exploiting Q-switched $2^{nd}$ harmonic Nd:YAG laser engraving system, and the effect of surface pattern in the brightness distribution of LGP was analysed. To prove the feasibility of proposed method in the enhancement of LGP performance, we designed three different surface patterns on the inner-scatterer LGP. The experimental results has proved the potential in the application of surface pattern to increasing the brightness of inner-scatterer LGP.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2002.05a
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• pp.177-179
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• 2002

본 연구는 Ag와 Ce이 함유된 유리를 용융법에 의해 제조하였으며, 355nm Nd:YAG 펄스 레이저를 조사하였을 때의 광학적 특성과 열처리과정에서 발생하는 결정화의 변화과정에 대해 평가하였다. Ce이 함유된 유리는 환원 분위기에서 제조되었으며, Optical Absorption을 통하여 Ce$^{3+}$ 이온이 존재하는 유리의 흡수대역을 관찰하고자 하였다. Photo Luminescence(PL) 측정을 통해 Ce$^{3+}$ 이 존재하고 있음을 확인하였으며, Ce$^{3+}$ 이온의 5d$\longrightarrow$4f 전이를 관찰하였다. 이와같이 Ce$^{3+}$ 가 함유된 유리는 레이저를 조사하였을 경우 PL의 강도가 저하됨을 확인하였다. 열처리과정에서 발생하는 결정화현상을 고찰하기 위해 열분석을 실시하였으며, 레이저조사된 유리에서 최대결정화온도가 감소함을 관찰하였다.

• Proceedings of the KIEE Conference
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• 2008.11b
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• pp.89-91
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• 2008

Organic EL has been expected to adopt to a new styles of technology that make flat display after Tang & Vanslyke made good electric luminescence device in late 1980s. Their studies based on multi layer structure that consists of emitting layer and carrier transporting layer using proper organic material. But oxidization of organic layer by ITO, energy walls in both pole interface, contaminations of ITO surface, importance of protecting membrane, diffusive dimming of light to cathode organic layer, these causes of degradations are common facts of a macromolecule and micro molecule. We think these degradation caused by the impact of heat and electro-chemical factor, bulk effect and interface phenomenon, and raise a question.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.1878-1880
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• 2005

In this research, We investigated the effect of $O_2/O_3$ Plasma treatment of indium-tin oxide (ITO) surface on the performance of organic light emitting devices (OLEDs). The OLED had a structure of ITO/N,N'-diphenyl-N,N' -(3-methylphenyl)-1, 1'-biphenyl-4-4'-diamine (TPD)/Tris (8-hydroxyquinolinato) Aluminum $(Alq_3)/Al$. The ITO surface was treated by $O_2/O_3$ plasma with different RF power chamber pressure and exposure time. As a result, the emission efficiency of the OLEDs could be improved obviously.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.286.1-286.1
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• 2013

Nowadays, the glare towards the light-emitting diode (LED) lighting source has much attention due to its eco-friendly nature, reduced energy consumption, and low CO2 emission. LEDs can show versatile colors by changing the composition ratio of semiconductors. Phosphors re-emit light by absorbing light from LED, which is the key factor for emission. The endeavor to make replica of natural white light is increasing day by day. Industrially, blue LED chip crowned with a yellow phosphor coated lens gives low quality white light. Newly, many researchers are introducing modern approaches, adding red phosphor to the yellow phosphor to increase the quality of white light. Here, we synthesized structurally and chemically stable europium doped oxyapatite Ca8Gd2(PO4)6O2 nano-crystalline structures by a hydrothermal method. The ultrafine structures were formed due to the effect of ethylenediaminetetraacetic acid, which is confirmed by the transmission electron microscope images. The structural properties were analyzed using the X-ray diffraction patterns.