• Applied Science and Convergence Technology
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• v.26 no.6
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• pp.208-213
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• 2017

Flexible opto-electronic devices are developed on the insulating layer deposited stainless steel (STS) substrates. The silicon dioxide ($SiO_2$) material as the diffusion barrier of Fe and Cr atoms in addition to the electrical insulation between the electronic device and STS is processed using the plasma enhanced chemical vapor deposition method. Noble silver (Ag) films of approximately 100 nm thickness have been formed on $SiO_2$ deposited STS substrates by E-beam evaporation technique. The films then were annealed at $650^{\circ}C$ for 20 min using the rapid thermal annealing (RTA) technique. It was investigated the variation of the surface morphology due to the interaction between Ag films and $SiO_2$ layers after the RTA treatment. The results showed the movement of Si atoms in silver film from $SiO_2$. In addition, the structural investigation of Ag annealed at $650^{\circ}C$ indicated that the Ag film has the material property of p-type semiconductor and the bandgap of approximately 1 eV. Also, the films annealed at $650^{\circ}C$ showed reflection with sinusoidal oscillations due to optical interference of multiple reflections originated from films and substrate surfaces. Such changes can be attributed to both formation of $SiO_2$ on Ag film surface and agglomeration of silver film between particles due to annealing.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.3A
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• pp.443-450
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• 2000

Although designing a virtual topology for all-optical WDM wide-area networks has been extensively studied and several algorithms have been proposed, these algorithms assumed error-free communication between two nodes. However, noises from optical amplifiers and optical cross-connects can degraded the signal, resulting in a nonzero bit-error rate. In this paper, we investigate the effect of physical limitations on the virtual topology design. We show that for side-area all-optical networks where transmission distance is fairly long, virtual topology design algorithm that can determine the locations of opto-electronic(OE) and electro-optic(EO) conversions to set up a connection request with a high BER in a multihop manner.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1997.10a
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• pp.39-43
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• 1997

Mercurous chloride (Hg$_2$Cl$_2$) has many advantages in its applications to acousto-optic, and opto-electronic devices because it has the unique properties of a broad transmisson range, well into the far infra-red, a low acoustic velocity, a large birefringence, and a high acousto-optic figure of merit[1]. Hg$_2$Cl$_2$ has a high vapor pressure, hence single crystals are usually grown by physical vapor transport(PVT) method in closed silica glass ampoules. We discuss the application of the laser Doppler velocimetry to measure the flow field inside a closed ampoule. The experimental results, are discussed its relationship to computational model and compared to their expectations.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.91-94
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• 2004

We report on the opto-electronic properties of red, green, and blue poly (fluorene) co-polymer light-emitting devices (PLEDs) fabricated on a flexible plastic substrate. The plastic substrate used has a multi-layer structure with water vapor and oxygen transmission rates of less than $10^{-5}$ g/$cm^2$-day-atm and $10^{-7}$ cc/$cm^2$-day-atm, respectively. We obtained a wide range of color gamut and a maximum emission efficiency of 0.7, 10, and 1.7 cd/A for red, green, and blue PLEDs, respectively. Finally, a simple equivalent circuit model is proposed to simulate PLED current density-voltage characteristics.

• International Journal of Precision Engineering and Manufacturing
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• v.1 no.1
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• pp.49-55
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• 2000

The semiconductor industry relies on digital optical imaging for the overlay metrology of integrated circuit patterns. One critical performance demand in the particular application of digital imaging is placed on the edge resolution that is defined as the smallest detectable displacement of an edge from its image acquired in digital from. As the critical feature size of integrated circuit patterns reaches below 0.35 micrometers, the edge resolution is required to be less than 0.01 micrometers. This requirement is so stringent that fundamental behaviors of digital optical imaging need to be explored especially for the precision coordinate metrology. Our investigation reveals that the edge resolution shows quasi-random characteristics, not being simply deduced from relevant opto-electronic system parameters. Hence, a stochastic upper bound analysis is made to come up with the worst edge resolution that can statistically well predict actual indeterminate edge resolutions obtained with high magnification microscope objectives.

• Korean Journal of Materials Research
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• v.29 no.12
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• pp.753-756
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• 2019

Orthorhombic dysprosium manganite DyMnO₃ with single phase is synthesized using solid-state reaction technique and the crystal structure and dielectric properties as functions of temperature and frequency are investigated. Thermally activated dielectric relaxations are shown in the temperature dependence of the complex permittivity, and the respective peaks are found to be shifted to higher temperatures as the measuring frequency increases. In Arrhenius plots, activation energies of 0.32 and 0.24 eV for the high- and low-temperature relaxations are observed, respectively. Analysis of the relationship between the real and imaginary parts of the permittivity and the frequencies allows us to explain the dielectric behavior of DyMnO₃ ceramics by the universal dielectric response model. A separation of the intrinsic grain and grain boundary properties is achieved using an equivalent circuit model. The dielectric responses of this circuit are discerned by impedance spectroscopy study. The determined grain and grain boundary effects in the orthorhombic DyMnO₃ ceramics are responsible for the observed high- and low-temperature relaxations in the dielectric properties.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.74-75
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• 2006

In organic opto-electronic applications, such as light emitting diodes (LEDs) and photovoltaic devices (PVDs), the morphology of the active layer is of crucial importance. To control the morphology of the active layer the self-assembling properties of block copolymers was used. Several rod-coil semiconducting diblock copolymers consisting of a conjugated block and a second coil block functionalized with electron transporting and/or accepting materials (such as $C_{60}$) were synthesized. The conjugated block acting as light absorbing, electron donating and hole transporting material. The donor/acceptor photovoltaic devices performance with active layer the above mentioned semiconducting block copolymers will be presented.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.29A no.10
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• pp.29-34
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• 1992

JFET's with gate lengths ranging from 1$\mu$m to 8.3$\mu$m are successfully fabricated on InP substrate where the long haul (1.3$\mu$m~8.3$\mu$m) OEIC's(OptoElectronic Integrated Circuits) have been made. The pn junction of InP JFET's is made by co-implantation and RTA process. JFET's have etched-mesa-gate structure and the maximum gm larger than 90mS/mm was measured and this is the highest record in JFET's of such structure without S/D n$^{+}$ ion implantation. To maintain maximum g$_m$ should be well controlled the overetch of n-layer which inevitably occurs during etching off the unused p-layer. The I-V characteristic is checked during p-layer etch, for this purpose. A dc voltage gain of 11 is obtained from a preamplifier circuit thus fabricated.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.14 no.2
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• pp.50-57
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• 2004

Mercurous Bromide ($Hg_2Br_2$) crystals hold promise for many acousto-optic and opto-electronic applications. This material is prepared in closed ampoules by the physical vapor transport (PVT) growth method. We investigate the effects of solutal convection on the crystal growth rate in a horizontal configuration for diffusive-convection conditions and purely diffusion conditions achievable in a low gravity environment. Our results show that the growth rate is decreased by a factor of one-fourth with a ten reduction of gravitational acceleration near y = 2.0 cm. For 0.1 $g_O$ the growth rate pattern exhibits relatively flat which is intimately related to diffusion-dominated processes. The growth rate nonuniformity is regardless of aspect ratio across the interfacial positions from 0 to 1.5. Also, the effect of a factor of the ten reduction in the gravitational acceleration is same to both Ar = 5 and 2. The enlargement in the molecular weight of B from 50 to 500 by a factor 4 causes a decrease in the maximum growth rate by the same factor, indicative of the effect of solutal gradients.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.1047-1052
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• 2003

Controlling carrier transport in light emitting polymers is extremely important for their efficient use in organic opto-electronic devices [1]. Here we show that the interactions between single wall carbon nanotubes (SWNTs) and conjugated polymers can be used to modify the overall mobility of charge carriers within nanotube-polymer nanocomposites. By using a unique, double emitting-organic light emitting diodes (DE-OLEDs) structure. we have characterized the hole transport within electroluminescent nanocomposites (nanotubes in poly (m-phenylene vinylene-co-2,5-dioctoxy-p-phenylene) or PmPV). We have shown using this idea that single devices with color tunability can be fabricated. It is seen that SWNTs in PmPV are responsible for hole trapping, leading to shifts in the emission wavelengths. Our results could lead to improved organic optical amplifiers, semiconducting devices, and displays.