• 한국자기학회:학술대회 개요집
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• 한국자기학회 2011년도 자성 및 자성재료 국제학술대회
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• pp.153-154
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• 2011

• Applied Microscopy
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• 제46권3호
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• pp.164-166
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• 2016

Electron channeling contrast imaging (ECCI) is a powerful analyzing tool for identifying lattice defects like dislocations and twin boundaries. By using diffraction-based scanning electron microscopy technique, it enables microstructure analysis, which is comparable to that obtained by transmission electron microscopy that is mostly used in defect analysis. In this report, the optimal conditions for investigating crystal defects are suggested. We could obtain the best ECCI images when both acceleration voltage and probe current are high (30 kV and 20 nA). Also, shortening the working distance (6 mm) enhances the quality of defect imaging.

• Applied Microscopy
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• 제45권3호
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• pp.131-134
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• 2015

Here we show how by processing energy dispersive X-ray spectrometry (EDS) data obtained using highly sensitive, new generation EDS detectors in the AZtec LayerProbe software we can obtain data of sufficiently high quality to non-destructively measure the number of layers in two-dimensional (2D) $MoS_2$ and $MoS_2/WSe_2$ and thereby enable the characterization of working devices based on 2D materials. We compare the thickness measurements with EDS to results from atomic force microscopy measurements. We also show how we can use electron backscatter diffraction (EBSD) to address fabrication challenges of 2D materials. Results from EBSD analysis of individual flakes of exfoliated $MoS_2$ obtained using the Nordlys Nano detector are shown to aid a better understanding of the exfoliation process which is still widely used to produce 2D materials for research purposes.

• E2M - 전기 전자와 첨단 소재
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• 제9권6호
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• pp.616-625
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• 1996

본 고에서는 최첨단 주사형 마이크로프로브현미경의 최근동향에 대해 기술하고자 한다. SNOAM의 관찰분야에의 응용이라는 관점에서 광학소자, 반도체재료, 유기박막등의 미소영역에의 광학특성의 관찰이외에 생물분야에서는 형광표식한 시료의 형상상과 형광상의 대비에서 세포나 생체고분자의 기능 해명에도 이용 가능하다고 생각된다. 또한 광가공기술에의 응용이나 기억소자 기술에의 응용도 고려되어져 금후의 응용분야에의 발전이 기대된다. 다가오는 21세기 정보화사회에서는 분자.원자를 제어하는 기술이 중심기술이 될 것으로 확신되고 있다. 그러나 현재 우리주변 기술로서 분자. 원자를 단위로 하는 평가, 분석 기술은 거의 찾을 수 없다. 따라서 주사형 마이크로 프로브 현미경은 Nano-technology로서 장래 정보화사회에 중요한 평가.분석기술의 하나로서 정착될것으로 생각된다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.552-555
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• 2004

The reliability issue of the probe tip/recording media interface is one of the most crucial concerns in the Atomic Force Microscope (AFM)-based recording technology. In this work, the tribological characteristics of the probe/media interface were investigated by performing wear tests using an AFM. The ranges of applied normal load and sliding velocity for the wear test were 10 to 50nN and 2 to 20$\mu$m/s respectively. The damage of the probe tip was quantitatively as well as qualitatively characterized by Field Emission Scanning Probe Microscope (FESEM) analysis and calculated based on Archard s wear equation. It was shown that the wear coefficient of the probe tip was in the order of 10$^{-4}$ ~ 10$^{-3}$ , and significant contamination at the end of the probe tip was observed. Thus in order to implement the AFM-based recording technology, tribological optimization of the probe/media interface must be achieved.

• Progress in Superconductivity
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• 제13권1호
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• pp.34-39
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• 2011

본 연구를 통해서 초전도 선재 시료의 국소적인 영역에 대한 전류 밀도의 공간적인 분포를 시료의 손상 없는 비파괴적인 방법으로 LTSHPM을 통해서 1차원 2차원으로 형상화해 보았다. 그 결과 외부자기장에 의한 차폐전류의 흐름을 분석할 수 있었다. 또한 MPMS에서 외부자기장에 따른 자기모멘트를 측정한 결과와 LTSHPM을 통해 전류 밀도 분포를 분석한 결과를 비교해 볼 때 외부자기장에 의한 반자성의 크기와 자기모멘트로 인해 생기는 차폐전류가 100 Oe에서 최댓값을 가지는 일치하는 결과를 얻을 수 있었다. 그리고 세 가지의 평행한 브릿지에 흐르는 차폐전류를 2차원적으로 분석해 본 결과 시료 전체적으로 가장 바깥쪽으로 차폐전류가 흐르는 공통점을 확인해 볼 수 있었다.

• 한국세라믹학회지
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• 제42권5호
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• pp.359-365
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• 2005

Silicon nitride coating films with various ratios of nitrogen to silicon contents were prepared and characterized. The film was coated on silicon substrate by sputtering method with changing nitrogen gas flow rate in a chamber. The nitrogen to silicon ratio was found to have values in a range from 0 to 1.4. Coated film was characterized with scanning electron microscopy, transmission electron microscopy, electron probe microanalysis, nanoindentation scanning probe microscopy, x-ray photon spectrometry, and Raman spectrometry. Silicon nitride phase in all samples showed amorphous nature regardless of N/Si ratio. When N/Si ratio was 1.25, hardness and elastic modulus of silicon nitride film showed maximum with 22 GPa and 210 GPa, respectively. Those values decreased, when N/Si ratio was higher than 1.25. Raman spectrum showed that no silicon phase exist in the film. XPS result showed that the silicon-nitrogen bond was dominant way for atomic bonding in the film. The structure and property was explained with Random Bonding Model(RBM) which was consistent with the microstructure and chemistry analysis for the coating films.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.162.6-162
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• 2001

Confocal scanning microscopy (CSM) is an important instrument in a wide variety of imaging applications because of its ability to provide three-dimensional images of thick, volume specimens. The mechanism for two-dimensional beam scanning and optical sectioning has an important roe in CSM as the three-dimensional profiler. This optical sectioning property arises from the use of a point detector, which serves to attenuate the signals from out-of-focus. The intensity profile for the open loop scanning should be matched with its response for the standard. The non-linearity can be minimized with the optical sectioning or the optical probe of the closed loop control. This paper shows the mathematical expression of the light such as the extinction curve in the optical fields of system using AO deflector, the axial/lateral response experimentally when the error sources change, and the methods of optical sectioning. Thorough design of optical sectioner is crucial to the success of CSM in the field ...

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.83-86
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• 2004

Carbon nanotube (CNT) tips in tapping mode atomic force microscopy (AFM) enable very high-resolution imaging, measurements, and manipulation at the nanoscale. We present recent results based on experimental analysis that yield new insights into the dynamics of CNT probe tips in tapping mode AFM. Experimental measurements are presented of the frequency response and dynamic amplitude-distance data of a high-aspect-ratio multi-walled (MW) CNT tip to demonstrate the non-linear features including tip amplitude saturation preceding the dynamic buckling of the MWCNT. Surface scanning is performed using a MWCNT tip on a SiO$_2$ grating to verify the imaging instabilities associated with MWCNT buckling when used with normal control schemes in the tapping mode. Lastly, the choice of optimal setpoints for tapping mode control using CNT probe tip are discussed using the experimental results.

• 한국전기전자재료학회논문지
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• 제18권7호
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• pp.622-627
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• 2005

In this study, electrical properties of self-assembled dipyridinium dithioacetate molecule onto the Au(111) substrate is observed using Scanning Tunneling Microscopy(STM) by vortical structure of STM probe. At first, the Au(111) substrate is cleaned by piranha solution$(H_2SO_4:H_2O_2\;=\;3:1)$. Subsequently, 1 mM/ml of dipyridinium dithioacetate molecule is self-assembled onto the Au(111) surface. Using STM, the images of dipyridinium dithioacetate molecule which is self-assembled onto the Au(111) substrate, can be observed. In addition, the electrical properties(I-V) of dipyridinium dithioacetate can also be examined by using Scanning Tunneling Spectroscopy(STS). From the results of the measurement of the current-voltage(I-V), the property of Negative Differential Resistance(NDR) that shows the decreases of current according to the increases of voltage is observed. We found the NDR voltage of the dipyridinium dithioacetate is -1.42 V(negative region) and 1.30 V(positive region), respectively.