• Journal of the Korean Institute of Telematics and Electronics A
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• v.29A no.11
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• pp.106-112
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• 1992

In this paper, we analyze the structure characteristics of $As_{40}Se_{50-x}S_{x}Ge_{10}$ system bulk and thin films. As the results of XRD patterns, it identified amorphous state. In order to find the glass transition temperature($T_g$), crystallization($T_c$) and melting point ($T_m$)of bulk sample, it ascertained that TS1gT is 238$^{\circ}C$ in $As_{40}Se_{15}S_{35}Ge_{10}$, and 231$^{\circ}C$ in $As_{40}Se_{25}S_{25}Ge_{10}$ & $As_{40}Se_{50}Ge_{10}$ following the thernal analysis by DSC, DTA, & TGA method. Also it was confirmed the phase seperation of continuous phase and dispertion phase by the optical texture of polarizing microscope and $T_g$ near 20$0^{\circ}C$ in thin film. Therefore, it was found that it occurs the phase seperation of Ge-rich dontinuous phase and Se-rich dispersion phase following the EDS analysis of thin film and the surface SEM photograph.

• Journal of the Microelectronics and Packaging Society
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• v.11 no.3 s.32
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• pp.63-70
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• 2004

The structural, electrical properties of $(Ba, Sr)TiO_3[BSTO]/RuO_2$ thin films were examined by the addition of amorphous BSTO layer between crystlline BSTO film and $RuO_2$ substrate. We prepared BSTO films with double-layered structure, that is, amorphous layers deposited at $60^{\circ}C$ and crystalline films. Crystalline films were prepared at 550 on amorphous BSTO layer. The thickness of the amorphous layers was varied from 0 to 170 nm. During the deposition of crystalline films, the crystallization of the amorphous layers occurred and the structure was changed to circular while crystalline BSTO films showed columnar structure. Due to insufficient annealing effect, amorphous BSTO phase was observed when the thickness of the amorphous layers exceeded 30 nm. Amorphous BSTO layer could also prevent the formation of oxygen deficient region in $RuO_2$ surface. Leakage current of total BSTO films decreased with increasing amorphous layer thickness due to structural modifications. Dielectric constant showed maxi-mum value of 343 when amorphous layer thickness was 30 nm at which the improvement by grain growth and the degradation by amorphous phase were balanced.

• Journal of the Korean Ceramic Society
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• v.21 no.4
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• pp.349-354
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• 1984

The purpose of present study is to find the structure crystallization mechanism and physical properties in $TiO_2$ containing lead zinc borosilicate glass system. The experiments such as differential thermal analysis infrared spectral analysis. X-ray diffraction analysis and thermal expansion measurements have been done. Differential thermal analysis of coarse and fine glass powder showed bulk nucleating mechanism for high $TiO_2$ containing glasses and surface nucleation mechanism for low $TiO_2$ containing glasses. The prepared glasses crystallized to crystalline mixture of PbO.2ZnO. $B_2O_3$ .4PbO.2ZnO.$5B_2O_3$and 2PbO.ZnO.$B_2O_3$ when heat-treated in the range of 480 and 51$0^{\circ}C$ and crystallized to PbTiO3 when heat-treated at $600^{\circ}C$. Obtained crystalline phase of $PbTiO_3$ in glass matrix strongly affects to thermal expansion coefficient and the value of crystallized glass varied 68.0 to $107.1{\times}10-7$/$^{\circ}C$ depending on the amount of $TiO_2$added. Infrared spectral analysis showed that [$BO_3$] triangle and [$BO_3$] tetrahedral units were coexisted in the glass with high content of PbO.

• Journal of the Korean Ceramic Society
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• v.35 no.9
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• pp.945-952
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• 1998

Ferroelectric Sr0.8Bi2.4Ta2O9 stock solutions were prepared by MOD(Metaloganic Decompostion) process. The phase transformation for the layered perovskite of the SBT thin films by changing RTA(Rapid her-mal Annealing) temperatuer from 700$^{\circ}C$to 780$^{\circ}C$ were observed using XRD and SEM. Layered perovskite phase began to appear above 740$^{\circ}C$ and then SBT thin films were annealed at 800$^{\circ}C$ for 1hr for its com-plete crystallization. The specimens showed well shaped hysteresis curves without post annealing that car-ried out after deposition of Pt top electrode. The SBT thin films showed the asymmetric ferroelectric pro-perties. It was confirmed that the properties were caused by interface effect to SBT and electrode by leak-age current density measurement and asymmetric properties reduced by post annealing. At post annealing temperature of 800$^{\circ}C$ remanant polarization values (2Pr) were 6.7 9 ${\mu}$C/cm2 and those of leakage current densities were 3.73${\times}$10-7 1.32${\times}$10-6 A/cm2 at 3, 5V respectively. Also bismuth bonding types of SBT thin film surface were observed by XPS.

• Proceedings of the KAIS Fall Conference
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• 2010.11a
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• pp.318-322
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• 2010

NaZSM 5 was synthesized in an alkaline medium and impregnated with cerium oxide by wet method using cerium nitrate as the source for cerium. There TGA results shows decomposition of nitrate at $200^{\circ}C$. The ceria impregnated ZSM 5 materials were designated as NaZSM 5 (X) where X is the percent ceria impregnated (3, 5, 7, 11, 19%). They were characterized by XRD, SEM, EDAX, BET techniques. XRD analysis showed decrease in intensity of the patterns with the increase in the ceria loading but crystallization of ceria to larger size is evident for 11 and 19% loading. The surface area and pore volume decreased with increase in ceria loading. The maximum adsorption capacity of NaZSM 5 (5%) is 100.2 mg/g of sorbent. The ceria impregnated NaZSM 5's were found to be regenerable, selective and recyclable.

• Polymer(Korea)
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• v.25 no.5
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• pp.699-706
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• 2001

The effects of uniaxial drawing conditions on the molecular orientation of poly (ethylene 2,6-naphthalate) (PEN) are investigated. Birefringence measurements show that the orientation is significantly enhanced at high draw ratio, low drawing temperature, and fast drawing speed. The characteristics of orientation examined by FTIR- ATR dichroism method represent almost same results. Amorphous orientation function increases with drawing rate at $120^{\circ}C$, but it decreases with drawing rate at $141^{\circ}C$. These behaviors can be explained with the relation between crystallization and chain relaxation rates. It is observed that the orientation of PEN film is accompanied by significant alignment of the naphthalene rings of PEN parallel to the film surface.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.200-200
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• 2003

Polycrystalline Si(polysilicon) TFTs have opened a way for the next generation of display devices, due to their higher mobility of charge carriers relative to a-Si TFTs. The polysilicon W applications extend from the current Liquid Crystal Displays to the next generation Organic Light Emitting Diodes (OLED) displays. In particular, the OLED devices require a stricter control of properties of gate oxide layer, polysilicon layer, and their interface. The polysilicon layer is generally obtained by annealing thin film a-Si layer using techniques such as solid phase crystallization and excimer laser annealing. Typically laser-crystallized Si films have grain sizes of less than 1 micron, and their electrical/dielectric properties are strongly affected by the presence of grain boundaries. Impedance spectroscopy allows the frequency-dependent measurement of impedance and can be applied to inteface-controlled materials, resolving the respective contributions of grain boundaries, interfaces, and/or surface. Impedance spectroscopy was applied to laser-annealed Si thin films, using the electrodes which are designed specially for thin films. In order to understand the effect of grain size on physical properties, the amorphous Si was exposed to different laser energy densities, thereby varying the grain size of the resulting films. The microstructural characterization was carried out to accompany the electrical/dielectric properties obtained using the impedance spectroscopy, The correlation will be made between Si grain size and the corresponding electrical/dielectric properties. The ramifications will be discussed in conjunction with active-matrix thin film transistors for Active Matrix OLED.

• Transactions on Electrical and Electronic Materials
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• v.12 no.5
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• pp.209-212
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• 2011

Hafnium nitride (HfN) thin films were deposited onto a silicon substrate by inductive coupled nitrogen plasma-assisted radio frequency magnetron sputtering. The films were prepared without intentional substrate heating and a substrate negative bias voltage ($-V_b$) was varied from -50 to -150 V to accelerate the effects of nitrogen ions ($N^+$) on the substrate. X-ray diffractometer patterns showed that the structure of the films was strongly affected by the negative substrate bias voltage, and thin film crystallization in the HfN (100) plane was observed under deposition conditions of -100 $V_b$ (bias voltage). Atomic force microscopy results showed that surface roughness also varied significantly with substrate bias voltage. Films deposited under conditions of -150 $V_b$ (bias voltage) exhibited higher hardness than other films.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.9
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• pp.1416-1422
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• 2001

The objective of this work was to characterize mechanical properties of thermoplastic composites with various forming conditions in compression molding. Randomly oriented long glass fiber reinforced polypropylene(PP) was used in this work. The composite materials contained 20%, 30%, and 40% glass fiber by weight. Compression molding was conducted at various mold temperatures and charge sizes. The temperatures on the mold surface and at the material in the mid-plain were monitored during the molding. Differential Scanning Calorimeter was used to measure crystallinity at both in-side and out-side of the sheet material. Crystallinity at each temperature was also measured by X-ray diffractometer. Dimensional stability was studied at various conditions with the spring forward angle. Among the processing parameters, the crystallization time at the temperature above 130$^{\circ}C$, was found to be the most effective. Spring-forward angle was reduced and the tensile modulus was increased as the mold temperature increased.

• Journal of Powder Materials
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• v.19 no.6
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• pp.412-415
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• 2012

The quartz glasses were prepared by sintering of fumed silica powders and the effect of OH concentration on their surface on sintering was studied. Through the firing process, the fumed silica was crystallized from 1180 to $1260^{\circ}C$ region. The amount of hydroxyl group decreased with increase in calcination temperature and consequently the crystallization was prevented. A transparent quartz glass was obtained from fumed silica, previously calcined at $1000^{\circ}C$, by the sintering at $1250^{\circ}C$ for 1 h.