• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1696-1698
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• 2000

We give pressure stimulation into long chain fatty acid of LB thin films then manufacture a device under the accumulation condition that the state surface pressure is 20[mN/m]. In processing of a device manufacture, we can see the process is good from the change of a surface pressure for organic thin films and transfer ratio of area per molecule. The structure of manufactured device is Au/Arachidic acid/Al, the number of accumulated layers are 13, 17 and 19. The I-V characteristic of the device is measured from 0[V] to +1.5[V] and the capacitor. The maximum value of measured current is increased as the number of accumulated layers are decreased. The capacitor properties of a thin film is better as the distance between electrodes is smaller.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1511-1514
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• 2009

Organic light emitting layer in OLED device was formed by gravure printing process in this work. Organic surface coated by gravure printing typically showed relatively bad uniformity. Thickness and roughness control was characterized by applying various mixed solvents in this work. Poly (N-vinyl carbazole) (PVK) and fact-tris(2-phenylpyridine)iridium($Ir(ppy)_3$) are host dopant system materials. PVK was used as a host and Ir(ppy)3 as green-emitting dopant. To luminance efficiency of the plasma treatment on etched ITO glass and then PEDOT:PSS spin coated. The device layer structure of OLED devices is as follow Glass/ITO/PEDOT:PSS/PVK+Ir(ppy)3-Active layer /LiF/Al. It was printed by gravure printing technology for polymer light emitting diode (PLED). To control the thickness multi-printing technique was applied. As the number of the printing was increased the thickness enhancement was increased. To control the roughness of organic layer film, thermal annealing process was applied. The annealing temperature was varied from room temperature, $40^{\circ}C$, $80^{\circ}C$, to $120^{\circ}C$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.10
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• pp.840-846
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• 2000

In this work, small-size, high-performance solenoid-type RF chip inductors utilizing a low-loss Al$_2$O$_3$core material were investigated. The size of the chip inductors fabricated in this work were 15$\times$10$\times$0.7㎣, 2.1$\times$1.5$\times$10㎣, and 2.4$\times$2.0$\times$1.4㎣ and copper (Cu) wire with 40 ㎛ diameter was used as the coils. High frequency characteristics of the inductance, quality factor, and impedance of developed inductors were measured suing an RF Impedance/Material Analyzer (HP4291B with HP16193A test fixture). It was observed that the developed inductors with the number of turns of 7 have the inductance of 33 to 100nH and exhibit the self-resonant frequency (SRF) of .26 to 1.1 GHz. The SRF of inductors decreases with increasing the inductance and the inductors have the quality factor of 60 to 80 in the frequency range of 300 MHz to 1.1 GHz. In this study, small-size solenoid-type RF chip inductors with high inductance and high quality factor were fabricated successfully. It is suggested that the thin film-type inductor is necessary to fabricate the smaller size inductors at the expence of inductance and quality factor values.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.913-919
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• 2000

We give pressure stimulation into long chain fatty acid of LB thin films then manufacture a device under the accumulation condition that the state surface pressure is 20[mN/m]. In processing of a device manufacture, we can see the process is good from the change of a surface pressure for organic thin films and transfer ratio of area per molecule. The structure of manufactured device is Au/Arachidic acid/Al, the number of accumulated layers are 13, 17 and 19. The I-V characteristic of the device is measured from 0[V] to +1.5[V]. We have investigated the capacitance because this fatty acid system have a accumulated layers. The maximum value of measured current is increased as the number of accumulated layers are decreased. The capacitor properties of a thin film is better as the distance between electrodes is smaller. The results have shown the insulating materials and could control the conductivity by accumulated layers.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.6
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• pp.568-573
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• 2006

We have synthesized new blue light emitting random copolymers, poly(9,9'-n-dioctylfluorene-co-perfluorobenzene-1,4-diyl)s (PFFBs), via Ni(0)-mediated coupling reactions. The weight-average molecular weights ($M_w$) of the PFFB copolymers ranged from 9,000 to 15,000. The PFFB copolymers dissolved in common organic solvents such as THF and toluene. The PL emission peaks of the PFFB copolymers were at around 420, 440, and 470 nm. EL devices were fabricated in ITO/PEDOT/polymer/Ca/Al configurations using these polymers. These EL devices were found to exhibit pure blue emission with approximate CIE coordinates of (0.15, 0.11) at $100cd/m^2$. The blue emissions of these devices might be due to the restriction of the polymer chains to aggregation by introducing of the highly electronegative fluorine moieties. The maximum brightnesses of the PFFB copolymer devices ranged from 140 to $3600cd/m^2$ with maximum efficiencies from 0.2 to 0.6 cd/A. The enhanced efficiency of the PFFB (8/2) copolymer device results from the inhibition of excimer formation by the introduction of the electronegative fluorine moieties into the copolymers.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.10
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• pp.811-816
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• 2012

The effect of co-sputtering condition on the structural properties of $Mg_xZn_{1-x}O$ thin films grown by RF magnetron co-sputtering system was investigated for manufacturing ZnO/MgZnO structure LED. $Mg_xZn_{1-x}O$ thin films were grown with ZnO and MgO target varying RF power. Structural properties were investigated by X-ray diffraction (XRD) and Energy dispersive spectroscopy (EDS). The ZnO thin films have sufficient crystallinity on the high RF power. As RF power of ZnO target increased, the contents of MgO in the $Mg_xZn_{1-x}O$ film decreased. LED was manufactured using ZnO/MgZnO multi-layer on p-GaN/$Al_2O_3$ substrate. Threshold voltage of multi-layer LED was appeared at 8 V, and it was luminesced at wave length of 550 nm.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.1
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• pp.80-84
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• 2014

The discharge characteristics of Surface Dielectric Barrier Discharge (SDBD) reactor are investigated to find optimal driving condition with adjusting various parameter. When the high voltage with sine wave form is applied to SDBD source, successive pulsed current waveforms are observed owing to multiple ignitions through the long discharge channel and wall charge accumulation on the dielectric surface. The discharge voltage, total charge between dielectrics, mean energy and power are calculated from measured current and voltage according to electrode gap and dielectric thickness. Discharge mode transition from filamentary to diffusive glow is observed for narrow gap and high applied voltage case. However, when the diffusive discharge is occurred with high applied voltage, the actual firing voltage is always lower than that with low driving voltage. The $Si_3N_4$, $MgF_2$, $Al_2O_3$ and $TiO_2$ are considered for dielectric protection and high secondary electron emission coefficient. SDBD with $MgF_2$ shows the lowest breakdown voltage. $MgF_2$ thin film is proposed as a protection layer for low voltage atmospheric dielectric barrier discharge devices.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.37-38
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• 2007

This paper reports the characteristics of piezoelectric microspeakers that are audible in open air with high quality piezoelectric AlN thin film according to the materials properties. When we use a tensile-stressed silicon nitride diaphragm as a supporting layer, the Sound Pressure Level (SPL) is relatively small. However, the SPL of the fabricated microspeakers that have compressive-stressed composite diaphragm show higher output pressure than those of tensile-stressed diaphragm. It produces more than 60dB from 100Hz to 15kHz and the highest SPL is about 100dB at 9.3kHz with 20 Vpeak-to-peak sinusoidal input biases and at 10 mm distances from the fabricated microspeakers to the reference microphone.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.4
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• pp.357-362
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• 2007

AZO(Aluminum-doped Zinc Oxide) films are attractive materials as transparent conductive electrode because they are inexpensive, nontoxic and abundant element compared with ITO(Indium Tin Oxide). AZO films have been deposited on glass (corning 1737) substrates by RF magnetron sputtering. The AZO film was post-annealed at $600^{\circ}C$ for 2 hr with $N_2$ atmosphere. The AZO films were used as an anode contact to fabricate OLEDs(Organic Light Emitting Diodes). OLEDs with $AZO/TPD/Alq_3/Al$ configuration were fabricated by thermal evaporation. We investigated that the electric, structural and optical properties of AZO thin films, which measured using the methods of XRD, SEM, Hall measurement and Spectrophotometer. The current density-voltage and luminescence-voltage properties of devices were studied and compared with ITO devices fabricated under the same conditions.

• Proceedings of the KAIS Fall Conference
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• 2007.11a
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• pp.133-135
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• 2007

PMMA (polymethyl metha crylate) 유기막의 농도별 최적화를 위하여 1, 2, 4, 6, 8 wt.%의 PMMA 농도별로 Al/PMMA/ITO/Glass 구조의 MIM (metal- insulator-metal) 캐패시터 소자를 제작하였다. 유기 절연층의 형성은 ITO/Glass 기판 위에 PMMA를 용질로, Anisle을 용매로 사용하여 스핀코팅법으로 소자를 형성하였다. 제작된 소자에 대해 농도에 따른 전기적 특성을 조사한 결과 누설전류는 2wt.% 농도의 PMMA로 제작된 소자에서 0.3 pA로 가장 우수한 결과를 얻을 수 있었다. 또한 동일한 PMMA 농도로 제작된 캐패시터 소자의 정전용량은 1.2 nF으로 가장 좋은 결과를 얻을 수 있었으며, 계산된 값과 매우 유사한 값을 얻을 수 있었다.