• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.33-34
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• 2008

$Ge_1Se_1Te_2$ chalcogenide amorphous materials was prepared by the conventional melt-quenching method. Samples were prepared by e-beam evaporator system and thermal evaporator technique. The thermal properties were investigated in the temperature range 300K-400K and the electrical properties were studied in the voltage range from 0V to 3V below the corresponding glass trasition temperature. The obtained results agree with the electrothermal model for Phase-Change Random Access Memory.

• Proceedings of the KIEE Conference
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• 2003.10a
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• pp.120-122
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• 2003

We have been investigated phase-change with temperature and electric field in chalcogenide $Ge_2Sb_2Te_5$ thin film. $T_c$(crystallization temperature) is confirmed by measuring the resistance and conductivity with the varying temperature on the hotplate. We have measured I-V characteristics with $Ge_2Sb_2Te_5$ chalcogenide thin film. It is compared with I-V characteristics after impress the variable pulse. The pulse has variable height and duration that used voltage and current source.

• Transactions on Electrical and Electronic Materials
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• v.7 no.3
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• pp.141-144
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• 2006

In the present work, we investigated the holographic grating erasing method by means of the optical method. It was formed the grating under the interference of holographic recording He-Ne laser beams on chalcogenide $As_{40}Ge_{10}Se_{15}S_{35}$ thin film with various film thickness and erased the holographic grating by non-polarized He-Ne laser beam. As the results, the recording grating erased the 80 % of formed grating by non-polarized He-Ne laser beam. It was confirmed that the erasing characteristics by non-polarized laser beam need to improve the focusing of beam and the control of beam intensity. And then it can be expected as the application possibility of rewritable holographic memory technology.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1331-1332
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• 2007

In the present works, we investigate the thermal characteristics on Ag/$As_{2}S_{3}$ and Ag/$As_{40}Ge_{10}Se_{15}S_{35}$ amorphous chalcogenide thin film structure for PMC (Programmable Metallization Cell).As the results of resistance change with the temperature on Ag/$As_{40}Ge_{10}Se_{15}S_{35}$ amorphous chalcogenide thin film, the resistance was abruptly dropped from the initial resistance of 1.32 M ${\Omega}$ to the saturated value of 800 ${\Omega}$ at $203^{\circ}C$. On the other hand, the resistance increased to 1.3 $M{\Omega}$ at $219^{\circ}C$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.12
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• pp.1022-1026
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• 2007

We have demonstrated new functionalities of Ag doped chalcogenide glasses based on their capabilities as solid electrolytes. Formation of such amorphous systems by the introduction of silver via photo-induced diffusion in thin chalcogenide films is considered. The influence of silver on the properties of the newly formed materials is regarded in terms of diffusion kinetics and Ag saturation is related to the composition of the hosting material. Silver saturated chalcogenide glasses have been used in the formation of solid electrolyte which is the active medium in programmable metallization cell (PMC) devices. In this paper, we investigated electrical and optical properties of Ag-doped chalcogenide thin film on changed thickness of Ag and chalcogenide thin films, which is concerned at Ag-doping effect of PMC cell. As a result, when thickness of Ag and chalcogenide thin film was 30 nm and 50 nm respectively, device have excellent characteristics.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.6
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• pp.580-583
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• 2008

In this paper, we investigated the properties of chalcogenide glass thin films formed by photo-inducing for use in 1-dimensional photonic crystals. We used Ag-doped amorphous As-Ge-Se-S thin films which belongs in the chalcogenide materials having sensitive photoluminescence properties. The purpose of this experiment is to form the holographic lattice for 1-dimensional photonic crystals. The way in which photo-induce into the amorphous chalcogenide thin films is holographic lithography method. We confirmed the formation of diffraction lattice by sensing the existence of diffraction beam and measured the diffraction efficiency. The results suggest that there is an application possibility with photonic crystals.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.248-248
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• 2010

We have demonstrated new functionalities of Ag-doped chalcogenide glasses based on their capabilities as solid electrolytes. The influence of silver on the properties of the newly formed materials is regarded in terms of diffusion kinetics, and Ag saturation is related to the composition of the hosting material. Silver saturated in chalcogenide glass has been used in the formation of solid electrolyte, which is the active medium in the programmable metallization cell (PMC) device. In this paper, we investigated the optical properties of Ag-doped chalcogenide thin film by He-Ne laser beam exposure, which is concerned with the Ag-doping effect of PMCs before or after annealing. Chalcogenide bulk glass was fabricated by a conventional melt quenching technique. Amorphous chalcogenide and Ag thin films were prepared by e-beam evaporation at a deposition rate of about $4\;{\AA}/sec$. As a result of resistance change with laser beam exposure, the resistance abruptly dropped from the initial value of $1.4\;M{\Omega}$ to the saturated value of $400\;{\Omega}$.

• Transactions on Electrical and Electronic Materials
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• v.9 no.6
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• pp.227-230
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• 2008

Programmable Metallization Cell (PMC) Random Access Memory is based on the electrochemical growth and removal of electrical nanoscale pathways in thin films of solid electrolytes. In this study, we investigated the nature of thin films formed by the photo doping of copper ions into chalcogenide materials for use in programmable metallization cell devices. These devices rely on metal ions transport in the film so produced to create electrically programmable resistance states. The results imply that a Cu-rich phase separates owing to the reaction of Cu with free atoms from chalcogenide materials.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.10a
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• pp.3.1-3.1
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• 2011

Nanoengineered materials with advanced architectures are critical building blocks to modulate conventional material properties or amplify interface behavior for enhanced device performance. While several techniques exist for creating one dimensional heterostructures, electrospinning has emerged as a versatile, scalable, and cost-effective method to synthesize ultra-long nanofibers with controlled diameter (a few nanometres to several micrometres) and composition. In addition, different morphologies (e.g., nano-webs, beaded or smooth cylindrical fibers, and nanoribbons) and structures (e.g., core-.shell, hollow, branched, helical and porous structures) can be readily obtained by controlling different processing parameters. Although various nanofibers including polymers, carbon, ceramics and metals have been synthesized using direct electrospinning or through post-spinning processes, limited works were reported on the compound semiconducting nanofibers because of incompatibility of precursors. In this work, we combined electrospinning and galvanic displacement reaction to demonstrate cost-effective high throughput fabrication of ultra-long hollow semiconducting chalcogen and chalcogenide nanofibers. This procedure exploits electrospinning to fabricate ultra-long sacrificial nanofibers with controlled dimensions, morphology, and crystal structures, providing a large material database to tune electrode potentials, thereby imparting control over the composition and shape of the nanostructures that evolved during galvanic displacement reaction.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1289-1290
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• 2008

Programmable Metallization Cell (PMC) is a memory device based on the electrolytical characteristic of chalcogenide materials. In this study, we investigate the nature of thin films formed by photo doping of Cu ions into chalcogenide materials for use in solid electrolyte of programmable metallization cell devices. We were able to do more economical approach by using copper which play an electrolyte ions role. The results imply that a Cu-rich phase separates owing to the reaction of Cu with free atoms from chalcogenide materials.