• Journal of Korean Vacuum Science & Technology
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• v.3 no.1
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• pp.79-84
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• 1999

the photolithographic patterning on an indium-tin oxide (ITO) glass and the electro-phoretic deposition were combined for preparing the screen of the full-color field emission display(FED). the patterns with a pixel of 400$\mu\textrm{m}$ on the ITO-glass were made by etching the ITO with well-prepared etchant consisting of HCL, H2O, and HNO3. Electrophoretic method was carried out in order to deposit each spherical red (R), green(G), and blue (B) phosphor on the patterned ITO-glass. The process parameters such as bias voltage, salt concentration, and deposition time were optimized to achieve clear boundaries. It was found that the etching process of ITO combined with electrophoretic method was cost-effective, provided distinct pattern, and even reduced process steps compared with conventional processes. The application of reverse bias to the dormant electrodes while depositing the phosphors on the stripe pattern was found to be very critical for preventing the cross-contamination of each phosphor in a pixel.

• Journal of the Korean Chemical Society
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• v.46 no.4
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• pp.336-345
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• 2002

In this study, we have screened $Eu^{3+}$- and $Tb^{3+}$-activated candidate phosphors for PDP in the sys-tems of CaO-Gd$_2$O$_3$-Al$_2$O$_3$ by combinatorial chemistry and investigated the synthetic temperature, optimum com-position and luminescent properties about the candidate phosphors. To construct the emission intensity library by VUV PL, we have synthesized 210 different compositional samples using a polymerized-complex method. Good luminescent samples were identified by X-ray diffraction method. $Ca_$\alpha$$G$d_{0.95-$\alpha$-$\beta$}Al_$\beta$O_$\delta$$ : Eu(0.02< $\alpha$+$\beta$ <0.04) phos-phors screened as a red phosphor have good color purity than commercial phosphor. In the candidate phosphors of CaGdAl$_3O_7$ : Tb, Ca$Al_{12}O_{19}$ : Tb, Gd$_4$Al$_2O_9$ : Tb, and Gd$_3Al_5O_{12}$ : Tb CaGdAl$_3O_7$ : Tb, and Ca$Al_{12}O_{19}$ : Tb have shorter decay time than commercial phosphor.

• Journal of the Korean Ceramic Society
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• v.48 no.3
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• pp.241-245
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• 2011

A red strontium aluminate phosphor ($Sr_3Al_2O_6:Eu^{3+},Eu^{2+}$) is synthesized using a solid state reaction method in air and reducing atmosphere. The investigation of firing temperature indicates that a single phase of $Sr_3Al_2O_6$ is formed when the firing temperature is higher than $1300^{\circ}C$. The effect of firing temperature and doping concentration on luminescent properties are investigated. $Sr_3Al_2O_6$ phosphor exhibits the typical red luminescent properties of $Eu^{3+}$ and $Eu^{2+}$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.1
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• pp.14-17
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• 2010

$ZnGa_2O_4$ powder were prepared by combustion method and $Mn^{2+}$ ions, a green luminescence activator, and $Cr^{3+}$ ions, a red luminescence activator were separately doped into $ZnGa_2O_4$. The characteristics of the synthesized nano powder were investigated by means of X-ray diffraction (XRD), Scanning Electron Microscope (SEM), and photoluminescence (PL). The various $ZnGa_2O_4$ peaks, with the (311) main peak, appeared at all sintering temperature XRD patterns. The PL specctrums of $ZnGa_2O_4$ powder showed main peak of 425 nm, and maximum intensity at the sintering temperature of $1200^{\circ}C$. SEM images shown that nano sized particles(about 200 nm) were of spherical shape. The characteristics of $ZnGa_2O_4$ containing 0.004 mol $Mn^{2+}$(505 nm, green) and $ZnGa_2O_4$ containg 0.002 mol $Cr^{3+}$ (696 nm, red) were shown to be the best.

• Current Applied Physics
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• v.18 no.11
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• pp.1225-1229
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• 2018

In this paper, we investigated the electronic structures and defect states of $SrLaMgTaO_6$ (SLMTO) double perovskite structures by using resonant inelastic x-ray scattering. Recently, $Eu^{3+}$ doped SLMTO red phosphors have been vigorously investigated due to their higher red emission efficiency compared to commercial white light emitting diodes (W-LED). However, a comprehensive understanding on the electronic structures and defect states of host SLMTO compounds, which are specifically related to the W-LED and photoluminescence (PL), is far from complete. Here, we found that the PL spectra of SLMTO powder compounds sintered at a higher temperature, $1400^{\circ}C$, were weaker in the blue emission regions (at around 400 nm) and became enhanced in near infrared (NIR) regions compared to those sintered at $1200^{\circ}C$. To elucidate the difference of the PL spectra, we performed resonant inelastic x-ray spectroscopy (RIXS) at Ta L-edge. Our RIXS result implies that the microscopic origin of different PL spectra is not relevant to the Ta-related defects and oxygen vacancies.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.36 no.5
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• pp.494-499
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• 2023

In this paper, in order to apply the CF (color filter) type of the micro light emitting device (Micro LED) display method, a study on the manufacturing process of red and green phosphor inks for the inkjet process was conducted. The blue light-emitting KSF and LuAG phosphors were respectively used to control the phosphor particle size to about 1㎛, and a phosphor ink was prepared by synthesizing with a low-viscosity solution (IPA/Eg). A chemical dispersion method was applied to selectively control the dispersion characteristics in the manufacture of phosphor inks, and in particular, phosphor inks with a dispersant applied a dispersant secured stable dispersion characteristic compared to phosphor inks without a dispersion process. Therefore, it seems possible to manufacture CF for Micro LED through an inkjet process capable of controlling the dispersion characteristics of phosphor ink.

• Journal of the Microelectronics and Packaging Society
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• v.14 no.4
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• pp.87-92
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• 2007

A $CaAl_{12}O_{19}:Mn^{4+}$ red phosphor showed the highest emission intensity at a concentration of 0.02mole $Mn^{4+}$ and the high crystallinity and luminescent properties were obtained at $1600^{\circ}C$ firing temperature for 3hr. The synthesized phosphor showed a broad emission band at 658nm wavelength. Red light-emitting diodes(LEDs) were fabricated through the integration of on InGaN UV bare chip and a 1:3 ratio of $CaAl_{12}O_{19}:Mn^{4+}$ and epoxy resin in a single package. This coated LED can be applicable to make White LEDs under excitation energy of UV LED.

• Journal of the Korean Chemical Society
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• v.49 no.2
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• pp.138-144
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• 2005

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.198-198
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• 2003

LED(Light Emitting Diode)는 전기 신호를 빛으로 신호를 보내고 받는데 사용되는 반도체의 일종으로 가정용 가전제품, 리모컨, 전광판, 각종 자동화 기기등에 사용된다. 3색광 백색 LED는 soft-UV 또는 blue 빛을 내는 device 와 RGB 형광체로 이루어져 있다. 현재 연구중인 3색광 백색 LED는 InGaN 또는 GaN 이 RGB 형광체를 여기 시키는것이 대부분이다. 이러한 경우에 유기물과 무기물 형과체가 백색광을 구현하기 위해 사용된다. 유기물의 경우에는 lift-time 이 짧고, 무기물의 경우에는 유해원소인 S, Cd등이 포함되기 때문에 환경오염이 야기된다. 이러한 단점을 보완하기 위해 진화 최적방법을 이용하여 alkali earth borosilicate ((Eu,Mg,Ca,Sr,Ba)$_{x}$ $B_{y}$ S $i_{z}$ $O_{d}$ ) 계열에 $^{Eu3+}$을 도핑하여 고효율 형광체를 합성하였다.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.895-897
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• 2008

ZnO films were fabricated using rf-magnetron sputter deposition process with different $N_2$ ambient. N-content in N-doped ZnO films was less than 1%. The wavelength of the highest intensity PL peak of N-doped ZnO was shifted to higher wavelength with increasing $N_2$ flow rate in the deposition ambient. These results indicated that the optical property of ZnO was significantly affected by the defect level created by doping with a very small amount of N.