• Applied Microscopy
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• 제44권4호
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• pp.133-137
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• 2014

We suggest a facile transmission electron microscopy (TEM) specimen preparation method for the direct (polymer-free) transfer of layer-area graphene from Cu substrates to a TEM grid. The standard (polymer-based) method and direct transfer method were by TEM, high-resolution TEM, and energy dispersive X-ray spectroscopy (EDS). The folds and crystalline particles were formed in a graphene specimen by the standard method, while the graphene specimen by the direct method with a new etchant solution exhibited clean and full coverage of the graphene surface, which reduced several wet chemical steps and accompanying mechanical stresses and avoided formation of the oxide metal.

• Applied Microscopy
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• 제48권2호
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• pp.49-53
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• 2018

A successful transmission electron microscope (TEM) analysis is closely related to the preparation of the TEM specimen and should be followed by the suitable TEM specimen preparation depending on the purpose of analysis and the subject materials. In the case of the Si-based anode material, lithium atoms of formed Li silicide were removed due to ion beam and electron beam during TEM specimen preparation and TEM observation. To overcome the problem, we proposed a new technique to make a TEM specimen without the ion beam damage. In this study, two types of test specimens from the Si-based anode material of Li-ion battery were prepared by respectively adopting the only focused ion beam (FIB) method and the new FIB-ultramicrotome method. TEM analyses of two samples were conducted to compare the Ga ion damage of the test specimen.

• Applied Microscopy
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• 제32권4호
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• pp.311-317
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• 2002

입자 크기에 따라 상전이 경로가 달라지며 매우 큰 응집체로 존재하는 gibbsite 분말과 같은 재료의 정량적인 전이 구조 분석의 전제로서 입자 크기가 선택적인 TEM 시편의 준비가 절실히 요구된다. 입자 크기 선택성을 실현한 TEM 시편 준비의 방법론을 확립하기 위한 방안으로서 본 실험이 전개되었다. 약 1 wt%의 gibbsite 원료 분말을 에탄올 용매에 혼합 한 뒤, ball-milling에 의해 조분쇄 처리를 하고 증류수에 1 : 19의 비로 희석된 분산 조제, Darvan C, 0.25 vol%의 첨가와 함께 ultrasonic 처리를 하여 gibbsite suspension을 만들었다. 제조된 gibbsite suspension의 누적 농도 변화 관찰에 의한 침강 시간의 조정 후 정적 침강 분리에 의해 nm 크기별로 분리된 TEM 시편을 만들 수가 있었다. 시편의 전체적인 양상은 SEM으로 관찰하였고 개개 입자들의 morphology 는 TEM으로 분석하였다. 또한, 공정 과정 중의 상변화 가능성을 검토하기 위해 XRD 분석을 실시하였다.

• Applied Microscopy
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• 제46권2호
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• pp.110-115
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• 2016

Transmission electron microscopy (TEM) is a powerful tool for analyzing a broad range of materials and provides localized information about the microstructure. However, the analysis results are strongly influenced by the quality of the thin foil specimen. Sample preparation for TEM analysis requires considerable skill, especially when the area of interest is small or the material of interest is difficult to thin because of its high hardness and its mechanical instability when thinned. This article selectively reviews recent advances in TEM sample preparation techniques using a tripod polisher. In particular, it introduces two typical types (fl at type and wedge type) of TEM sample preparation and the benefits and drawbacks of each method; finally, a method of making better samples for TEM analysis is suggested.

• Applied Microscopy
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• 제48권4호
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• pp.122-125
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• 2018

The focused ion beam (FIB) method is widely used to prepare specimens for observation by transmission electron microscopy (TEM), which offers a wide variety of imaging and analytical techniques. TEM has played a significant role in material investigation. However, the FIB method induces amorphization due to bombardment with the high-energy gallium ($Ga^+$) ion beam. To solve this problem, electron beam induced deposition (EBID) is used to form a protective layer to prevent damage to the specimen surface. In this study, we introduce an optimized TEM specimen preparation procedure by comparing the EBID of carbon and tungsten as protective layers in FIB. The selection of appropriate EBID conditions for preparing specimens for TEM analysis is described in detail.

• Applied Microscopy
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• 제39권3호
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• pp.277-281
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• 2009

Practical difficulties for preparing a good crosssectional specimen of GaN-based materials for transmission electron microscopy have arisen due to large difference of mechanical properties between hard ceramic substrate and soft GaN-layered materials. Uneven polishing, sudden cracking, delamination, and selective sputtering during the conventional wedge polishing technique are often encountered as experimental hindrances. The preparation technique based on Strecker's method can be applied to overcome these difficulties, which eventually leads to mechanically stable TEM samples independent of the mechanical properties of materials. The basic idea is to use hard ceramic dummy filler for embedding the sample of interest into the dummy frame. In this study, we applied this technique into preparing cross-sectional TEM specimen of the GaN-based materials with mechanical instability and demonstrated usefulness of this hard dummy filler method in which the possible modifications of the sample of interest during the preparation must be avoidable. In addition, practical precautions during the preparation were discussed.

• Applied Microscopy
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• 제45권4호
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• pp.195-198
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• 2015

Gas-assisted etching (GAE) with focused ion beam (FIB) was applied to prepare plan-view specimens of Cu thin-layer on a silicon substrate for transmission electron microscopy (TEM). GAE using $XeF_2$ gas selectively etched the silicon substrate without volume loss of the Cu thin-layer. The plan-view specimen of the Cu thin film prepared by FIB milling with GAE was observed by scanning electron microscopy and $C_S$-corrected high-resolution TEM to estimate the size and microstructure of the TEM specimen. The GAE with FIB technique overcame various artifacts of conventional FIB milling technique such as bending, shrinking and non-uniform thickness of the TEM specimens. The Cu thin film was uniform in thickness and relatively larger in size despite of the thickness of <200 nm.

• Applied Microscopy
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• 제29권4호
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• pp.493-498
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• 1999

기억저장매체로서 광디스크의 개발이 활발히 진행되고 있으며 최근의 레이저 기술의 발전, 제조기술의 발전에 따른 기억밀도의 증가로서 기존의 자기기록매체와 경쟁을 하고 있다. 기록밀도의 증대와 신뢰성의 향상을 위하여 다층박막 구조를 가지는 광디스크의 미세구조는 더욱 복잡하며 소형화되고 있다. 이종의 물질로 구성된 다층박막형 광디스크의 미세구조 관찰 및 분석을 위해서는 투과전자현미경과 같은 미소영역 분석법이 필수적이며 비교적 간단하고 신뢰성 높은 시편준비법의 확립이 선행되어야 한다. 본 연구에서는 투과전자현미경 분석을 위한 광디스크의 평면 및 단면시료 제작법을 제시하고 제조된 시편으로부터 얻어진 광디스크의 미세구조 분석결과를 보고한다.

• Applied Microscopy
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• 제29권1호
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• pp.67-73
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• 1999

분말시료를 epoxy로 포매 (embedding)한 후 ion milling하는 방법으로 TEM 시편을 준비하는 경우에는 시료와 epoxy와의 milling정도의 차이 때문에 좋은 시편을 만들기 어렵다. 이러한 문제점을 극복하기 위해서 포매 물질에 대한 분말시료의 상대 밀도를 높여 주는 방법을 시도하였다. 일반적인 진공법보다는 원심분리기법을 이용하여 포매하는 것이 시료의 밀도를 높일 수 있었다. 또한, 비슷한 크기의 분말의 혼합보다는 서로 다른 크기의 분말을 혼합한 후 원심분리기를 이용하여 포매할 때, 큰 입자들 사이로 작은 입자들이 유입되면서 분말의 밀도가 더욱 높아지는 것을 알 수 있었다. 이렇게 준비된 시료는 ion milling정도의 차이에서 오는 문제점을 크게 줄일 수가 있어 TEM 관찰에 필요한 시편을 얻을 수 있었다. 원심분리기법은 마이크로미터 이하 크기의 구형, 판상 및 침상의 분말시료에서부터 TEM 시편을 준비하는 데에도 매우 효과적임이 드러났다.

• Applied Microscopy
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• 제28권3호
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• pp.315-328
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• 1998

The present study was carried out to investigate the effect of ultrasonic bath in tissue preparation for transmission electron microscopy. The method used standard reagents and media, and employed ultrasonic bath agitation to accelerate fluid exchange. The liver kidney, stomach and cardiac muscle tissues of male Sprague-Dawley rats were used for the experiment, and the experimental design was divided into 4 groups; The control group using rotators (Traditional method, 1,625 mins) and the three experimental groups using ultrasonic bath (UB) in the primary fixation through the infiltration processes (UB I; 62.5 mins, UB II; 125 mins, UB III; 250 mins). The results were as follows; 1. In the control group, tissues were easily sectioned, and showed well preserved intact membranes, and cell organelles such as mitochondria, lysosome, peroxisome, rough endoplasmic reticulum and smooth endoplasmic reticulum. 2. In the UB treated group I, tissues showed holes due to the inadequate removal of both water and fluids used in the dehydration process. Also the mitochondria of cell organelles, especially, showed swollen intracristal spaces and dense matrices due to poor fixation. 3. In the UB treated group II, tissues showed good preservation of cell organelles and specimen slice sections. Also, no holes were observed. 4. In the UB treated group III, tissues showed leaching of structural components in the cytoplasm, but no holes were observed. In conclusion, the ultrasonic bath procedure takes approximately 120 minutes from specimen fixation to resin infiltration and gives excellent results.