• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.383-383
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• 2011

We fabricated thermal annealing-free polymer solar cells (PSC) by processing with additive and applied to flexible substrates. The 1, 8-Diiodooctane of 3 vol% blended with active solution resulted in enhancement of $J_{SC}$ due to increase of light absorption and hole mobility as improving the crystallinity of P3HT. In addition, the $V_{OC}$ of PSCs with additive was improved by inserting $TiO_2$ layer without any treatment. The $TiO_2$ layer prevented the direct contact between active layer and Al electrode and reduced the charge recombination near Active/Al interface. It was confirmed by calculation of J0 and photo-voltage transient measurement. The power conversion efficiencies of annealing-free PSCs using additive for ITO glass and flexible (ITO PEN) substrate were obtained 3.03% and 2.45%, respectively.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.846-849
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• 2009

In this study, we manufactured polymer-LED using light emitting copolymer as the active layer. After cathode layer deposition, we did post-annealing at $150^{\circ}C$ during 10 min in $N_2$ glove box. Then, we confirmed that the efficiency of the device was significantly enhanced by post annealing process. Its value was increased from 0.18(cd/A) to 1.32(cd/A), approximately 7 times. This phenomenon is a result of improved stability between polymer and metal cathode for injection of electrons as the contact density increases.

• Journal of Information Display
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• v.2 no.2
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• pp.7-12
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• 2001

A viscous Ni solution was coated over amorphous Si thin film for evenly spread of Ni metal source. The Ni s. prepared by dissolving $NiCl_2$ into IN HCI and mixing with propylene glycol. $NiCl_2$ and Ni were deposited on the amorphous film after oven dry and they enabled to obtain a uniform crystallization. The crystallization using the viscous Ni solution was a Ni-silicide mediated process, the same process used with Ni metal layer. The crystallization temperature was lowered to $480^{\circ}C$ by the synergy effect of silicide-mediated crystallization and microwave-induced crystallization. Lateral crystallization was also enhanced such that the velocity of lateral crystallization by microwave annealing became faster than by furnace annealing.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.49 no.12
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• pp.589-594
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• 2000

The fuzzy controllers have been applied to the power system stabilizer due to its excellent properties on the nonlinear systems. But the design process of fuzzy controller requires empirical and heuristic knowledge of human experts as well as many trial-and-errors in general. This process is time consuming task. This paper presents an parameters tuning method of the fuzzy power system stabilizer using the genetic algorithm and simulated annealing(SA). The proposed method searches the local minimum point using the simulated annealing algorithm. The proposed method is applied to the one-machine infinite-bus of a power system. Through the comparative simulation with conventional stabilizer and fuzzy stabilizer tuned by genetic algorithm under various operating conditions and system parameters, the robustness of fuzzy stabilizer tuned by proposed method with respect to the nonlinear power system is verified.

• Korean Journal of Materials Research
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• v.34 no.2
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• pp.79-84
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• 2024

Thin films of yttria-stabilized zirconia (YSZ) nanoparticles were prepared using a low-temperature deposition and crystallization process involving successive ionic layer adsorption and reaction (SILAR) or SILAR-Air spray Plus (SILAR-A+) methods, coupled with hydrothermal (175 ℃) and furnace (500 ℃) post-annealing. The annealed YSZ films resulted in crystalline products, and their phases of monoclinic, tetragonal, and cubic were categorized through X-ray diffraction analysis. The morphologies of the as-prepared films, fabricated by SILAR and SILAR-A+ processes, including hydrothermal dehydration and annealing, were characterized by the degree of surface cracking using scanning electron microscopy images. Additionally, the thicknesses of the YSZ thin films were compared by removing diffusion layers such as spectator anions and water accumulated during the air spray plus process. Crack-free YSZ thin films were successfully fabricated on glass substrates using the SILAR-A+ method, followed by hydrothermal and furnace annealing, making them suitable for application in solid oxide fuel cells.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.3
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• pp.638-642
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• 2014

In this study, we investigate on the crystal microstructure and magneto-resistance (MR) change of Bismuth(Bi) thin films for annealing process, in order to apply Bi thin films to the spin electronic devices. As-prepared Bi thin films show the randomly oriented find grains whose size was measured to about 100 nm and the very low MR (4.7 % at room temperature) while careful annealing results in not only grain growth up to ${\sim}2{\mu}m$ but also drastic MR improvement (404 % at room temperature). The drastic change in the MR after applying the annealing process is attributed to the grain growth decreasing grain boundary scattering of electron. Therefore, in this study, we confirm the annealing effect for the grain boundary formation and MR improvement of Bi thin films, and demonstrate the feasibility of spin electronic devices.

• Journal of the Korean Society for Heat Treatment
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• v.32 no.3
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• pp.107-112
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• 2019

In order to investigate the effect of plastic deformation and annealing process parameters on strength and electrical conductivity of Cu-Fe alloys, Cu-10wt%Fe, Cu-15wt%Fe alloys were drawn up to ${\eta}=4$ and annealed in the temperature range of $300^{\circ}C$ to $700^{\circ}C$, followed by measurements of tensile strength and electric conductivity. As draw strain increases, tensile strength increases while electrical conductivity decreases. These observations result from reduction of dislocation density and decrease in Fe fiber spacing. Raising annealing temperature brought about decrease of tensile strength and increase of electrical conductivity up to $500^{\circ}C$, being followed by decreasing above $500^{\circ}C$. Such results are thought to be caused by decrease of dislocation density below $500^{\circ}C$ and rapid solubility increase of Fe in Cu above $500^{\circ}C$. For the purpose of obtaining both high strength and high conductivity, annealing process should be incorporated just prior to reaching to final draw strain. For Cu-10wt%Fe alloy, the tensile strength 706.9 MPa and the electrical conductivity 54.34%IACS were obtained through the processes of drawing up to ${\eta}=3$, annealing at $500^{\circ}C$ for 1 hour and additional drawing up to total strain of ${\eta}=4$.

• Journal of the Korean Society for Heat Treatment
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• v.22 no.1
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• pp.23-26
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• 2009

Pt nanotubes with diameter of 200 nm were fabricated by simple and convenient method of Template-Wetting Process. Porous alumina membranes were prepared by 2 step anodic oxidation as the template. To improve wetting properties and lower surface energy, pt solution was mixed with polymer. Polymer was removed completely during annealing. Grain growth process of pt nanotubes during baking and furnace annealing was examined by FE-SEM and XRD.

• Journal of Sensor Science and Technology
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• v.25 no.4
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• pp.252-256
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• 2016

Epitaxially grown GaN layers have a high surface state density, which typically results in a surface leakage current and a photoresponse in undesirable wavelengths in GaN optoelectronic devices. Surface passivation is, therefore, an important process necessary to prevent performance degradation of GaN UV photodetectors. In this study, we propose oxygen-enhanced thermal treatment as a simple surface passivation process without capping layers. The GaN UV photodetector fabricated using a thermal annealing process exhibits improved electrical and photoresponsive characteristics such as a reduced dark current and an enhanced photoresponsive current and UV-to-visible rejection ratio. The results of this study show that the proposed surface passivation method would be useful to enhance the reliability of GaN-based optoelectronic devices.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.25-26
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• 2011

In this paper, we investigated the effect of various annealing processes on the electrical characteristics of oxide thin film transistors (TFTs). When we annealed the TFT devices before and after source/drain (S/D) process, we could observe the different electrical characteristics of oxide TFTs. When we annealed the TFTs after deposition of transparent indium zinc oxide S/D electrodes, the annealing process decreased the contact resistance but increased the resistivity of S/D electrodes. The field effect mobility, subthreshold slope and threshold voltage of the oxide TFTs annealed before and after S/D process were 5.83 and 4.47 $cm^2$/Vs, 1.20 and 0.82 V/dec, and 3.92 and 8.33 V respectively. To analyze the differences, we measured the contact resistances and the carrier concentrations using transfer length method (TLM) and Hall measurement.