• Electrical & Electronic Materials
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• v.10 no.7
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• pp.700-705
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• 1997

Transparent conducting indium tin oxide (TC-ITO) thin films are deposited on soda lime glass by a dc magnetron sputtering technique having the unbalanced-magnet structure in order to improve the electrical/material characteristics and to avoid the surface damages. The material properties are measured by the x-ray diffractometer (XRD) and atomic force microscope (AFM). The (400) peak as the preferred orientation of <100> direction for ITO thin films is stabilized with the increase of substrate temperature. The surface roughness estimated by AFM 3D image at the substrate temperature of 40$0^{\circ}C$ is extremely uniform. The best resistivity of ITO films (5500 $\AA$ thick) at 40$0^{\circ}C$ is about 1.3$\times$10$^{-4}$ $\Omega$cm on the position of 4 cm from substrate center.

• Journal of the Korean Magnetics Society
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• v.19 no.5
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• pp.176-179
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• 2009

We report a direct observation of Barkhausen avalanches in 50-nm Fe film, using a magneto-optical microscope magnetometer, capable of time-resolved domain observation. The time-resolved domain-evolution patterns exhibit that the occurrence of Barkhausen jump is random with respect to interval, size, and location. From the repetitive measurements more than 1000 times, we found that the probability distribution of Barkhausen jump size follows a power-law distribution and the critical exponent reveals the value of 1.14 $\pm$ 0.03.

• Proceedings of the KIEE Conference
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• 2003.10a
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• pp.316-318
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• 2003

본 연구에서는 전기적 특성, 기계적 특성, 내수성 및 내유성이 우수한 고분자 화합물로 산업용, 콘덴서절연재료용, 의료센서용 등 각종 절연재료 및 유전재료로 활용되어 지고 있는 변환기용 PET박막에 광자선을 10[Gy] 15[MeV], 30[Gy] 15[MeV], 50[Gy] 15[MeV]를 조사하여 물성분석 및 전기적 특성중 유전정접 특성에 관하여 검토하였다. 물성분석으로 X-선 회절(XRD) 분석 결과 조사량에 따라 피크의 크기가 커지므로 결정성이 더욱 좁아짐을 알수 있었으며 적외선 분광(FTIR) 측정결과로 파수 1752[$cm^{-1}$]에서는 C=O기의 신축운동 기여로 피크가 나타나며 파수 1266[$cm^{-1}$]에서 =C-O기의 신축운동기여와 그리고 1019[$cm^{-1}$]에서는 벤젠환의 진동기여로 흡수 피크가 나타남을 알 수 있었고, 전자현미경을 이용하여 800배로 확대한 시료의 파단면을 조사한 결과 결정질과 비정질 영역이 혼재하고 있는 것을 확인하였다. 유전정접 특성으로는 측정온도범위 상온에서 130[$^{\circ}C$]와 인가전압 범위 1[V]에서 20[V]를 변화시켜 각각의 조사량에 대한 PET 박막의 유전특성의 온도의존성 및 주파수 의존성에 대하여 실험한 결과 변환기 재료의 가능성을 조사하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.681-684
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• 2015

Magnetization is very important in the ferro-magnetic physics and provides useful informations in the application field of magnetic devices. Generally, the only first acquired domain pattern is not helpful to recognize domain pattern. Many images are needed to visualize domain pattern through image processing. These images were obtained a 8-bit digital camera. The operation was the subtraction of pixel values of multi domain imanges from the images with 255 of pixel value, which was obtained in the saturated state of magnetic materials. The magnetic domain images was visualized gradually with increasing the number of subtracion operation. LABVIEW was used as an image processing tool and the optic microscope with a polarizer was used in this experiment.

• Korean Journal of Optics and Photonics
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• v.33 no.5
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• pp.201-209
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• 2022

The previously developed microspot spectroscopic ellipsometer (SE) is upgraded to a microspot SE compatible with the atomic force microscope (AFM). The focusing optical system of the previous microspot SE is optimized to incorporate an AFM head. In addition, the rotating compensator ellipsometer in polarizer-sample-compensator-analyzer configuration is adopted in order to minimize the negative effects caused by beam wobble. This research leads to the derivation of the expressions needed to get spectro-ellipsometric constants despite the fact that the employed rotating compensator is far from the ideal achromatic quarter-wave plate. The spot size of the developed microspot SE is less than 20 ㎛ while the AFM head is mounted. It operates in the wavelength range of 190-850 nm and has a measurement accuracy of δΔ ≤ 0.05° and δΨ ≤ 0.02°, respectively. Fast measurement of ≤3 s/sp is realized by precisely synchronizing the azimuthal angle of a rotating compensator with the spectrograph. The microspot SE integrated with an AFM is expected to be useful in characterizing the structure and optical properties of finely patterned samples.

• Clean Technology
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• v.23 no.2
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• pp.196-204
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• 2017

CdZnS/ZnO composite was prepared through low-temperature precipitation and drying method. The property of CdZnS/ZnO as a recyclable photocatalyst for the degradation of rhodamine B (RhB) under visible light irradiation was examined. The sample was characterized by XRD, FE-SEM, XPS, UV-vis DRS and photoluminescence techniques before and after repeated reaction to investigate the change of properties during the photocatalytic reaction. During repeated reaction, the CdZnS/ZnO showed an improved photocatalytic activity and recycle stability. Among two feasible reaction pathways for photocatalytic degradation of RhB, the cleavage of conjugated chromophore was found to predominate over N-dealkylation of chromophore skeleton in the present work. The results indicate that the CdZnS/ZnO, prepared by a simple precipitation method, can be used as a visible-light driven photocatalyst with enhanced cycle stability and activity.