• Applied Microscopy
• /
• v.44 no.4
• /
• pp.138-143
• /
• 2014

Transmission electron microscope (TEM) is an excellent tool for studying the structure and properties of nanostructured materials. As the development of $C_s$-corrected TEM, the direct analysis of atomic structures of nanostructured materials can be performed in the high-resolution transmission electron microscopy (HRTEM). Especially, fast Fourier transform (FFT) technique in image processing is very useful way to determine the crystal structure of HRTEM images in reciprocal space. To apply FFT technique in HRTEM analysis in more reasonable and friendly manner, we made a new circular region of interest (C-ROI) FFT script and tested it for several HRTEM analysis. Consequentially, it was proved that the new FFT application shows more quantitative and clearer results than conventional FFT script by removing the streaky artifacts in FFT pattern images. Finally, it is expected that the new FFT script gives great advantages for quantitative interpretation of HRTEM images of many nanostructured materials.

• Applied Microscopy
• /
• v.50
• /
• pp.21.1-21.3
• /
• 2020

Sample preparation is significantly important to the high-resolution transmission electron microscopy (HRTEM) characterization of nanomaterials. However, many general organic solvents can dissolve the necessary organic polymer support layer in TEM grid, which causes it difficult to obtain high-quality samples of oil-soluble nanomaterials. In this study, a new sample preparation method for oil-soluble nanomaterials has been developed by using the sublimable material as a transition layer. Experiments also show that there is no damage to TEM grids and high-quality HRTEM images can be obtained via this method. This approach paves the way to applicable HRTEM sample preparation of oil-soluble nanomaterials.

• Journal of the Mineralogical Society of Korea
• /
• v.13 no.2
• /
• pp.84-95
• /
• 2000

Tremolite crystals from the Dongyang talc deposit were studied using high-resolution transmission electron microscopy (HRTEM) to characterize the tremolite-to-talc reaction. [001] HRTEM images of tremolite show intergrowths of wide-chain pyriboles and talc; talc is the primary alteration product of tremolite, and triple-chain structures occur sparsely. The boundaries between tremolite and talc are commonly well defined by (010) and (100) interfaces. (001) talc layers are parallel to (100) of tremolite, and the interfaces between tremolite and talc appear to be coherent in HRTEM images, indicating that most talc laters formed directly from tremolite by a gydration reaction. However, some talc formed along (110) of tremolite, and talc layers are not extended from (010) of tremolite, suggesting that part of talc in the deposit was produced through a dissolution-precipitation mechanism. Carbonate minerals are also associated with tremolite and talc. Common replacement of dolomite by calcite indicates that the tremolite-to-talc reaction results in remnant Ca, which was eventually consumed to replace dolomite to form clacite. Some Mg Produced by dolomite during reaction to calcite was apparently utilized to form talc, because talc formation from tremolite requires extra Mg. Although talc could be formend directly from dolomite, extensive alteration of tremolite to talc suggests that part of talc of the deposit was produced from tremolite that was formed by dolomite reaction during an early stage metamorphism.

• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.53 no.6
• /
• pp.312-315
• /
• 2004

The monolayer of oxygen atoms sandwiched between the adjacent nanocrystalline silicon layers was formed by ultra high vacuum-chemical vapor deposition (UHV-CVD). This multilayer Si-O structure forms a new type of superlattice, semiconductor-atomic superlattice (SAS). According to the experimental results, high-resolution cross-sectional transmission electron microscopy (HRTEM) shows epitaxial system. Also, the current-voltage (Ⅰ-Ⅴ) measurement results show the stable and good insulating behavior with high breakdown voltage. It is apparent that the system may form an epitaxially grown insulating layer as possible replacement of silicon-on-insulator (SOI), a scheme investigated as future generation of high efficient and high density CMOS on SOI.

• Korean Journal of Materials Research
• /
• v.17 no.8
• /
• pp.408-413
• /
• 2007

Process of the hydroxyapapite(HA) precipitation on bioactive titanium metal prepared by NaOH in a modified-simulated body fluid(mSBF) was investigated by high resolution transmission electron microscope (HRTEM) attached with energy dispersive X-ray spectrometer(EDX). The amorphous titanate phase on titanium surface is form by NaOH treatment and an amorphous titanate incorporated calcium and phosphate ions in the liquid to form an amorphous calcium phosphate. With increasing of soaking time in the liquid, the HA particles are observed in amorphous calcium phosphate phase with a Ca/P atomic ratio of I.30. The octacalcium phosphate (OCP) structure is not detected in HRTEM image and electron diffraction pattern. After a long soaking time, the HA particles grow as needle-like shape on titanium surface and a large particle-like aggregates of needle-like substance were observed to form on titanium surface within needle-like shape. A long axis of needle parallels to c-direction of the hexagonal HA structure.

• Proceedings of the Korean Vacuum Society Conference
• /
• 1999.07a
• /
• pp.74-74
• /
• 1999

TEM(투과전자현미경, Transmission Electron Microscop)은 결정재료뿐 아니라 비정질 재료까지도 원자단위의 구조를 연구하는데 매우 유용한 도구이다. 특히 200kV의 가속전압 투과전자현미경에 FEG(Field Emission Gun) 전자총이 장착되기 시작하면서 TEM은 비정질 구조 연구에 하나의 핵심적인 도구로서의 역할이 크게 기대되는 장비가 되었다. 본 연구에서는 TEM의 microanalysis accessary인 EELS(Electron Energy Loss Spectroscopy)technique을 주로 이용하던 기존의 방법대신 고 분해능(HRTEM(High Resolution Transmission Electron Microscopy)의 image로부터 비정질 정량묘사의 유일한 도구인 원자분포함수(RDF(Radial Distribution Function))로의 Reconstruction을 Simulation을 이용하여 시도하였다. 비정질 HRTEM image의 정량분석을 통하여 이 분야에서의 TEM의 한계를 이해하기 위하여 몇 모델을 제시하고 사용하였다. 또한 비정질 구조를 정량적으로 묘사하는 도구인 원자분포함수를 알아보고 비정질재료를 보다 물리적으로 모델링하기 위하여 가능한 모델 제시 후 첫 단계로서 HRTEM image에서 원자분포함수를 이끌어내기 위한 모델링을 수행하고 비정질 게르마늄(a-Ge) film에 대하여 실제로 적용하여 보았다. 마지막으로 실험적인 접근으로 200kV FE-TEm (poingt resolution 0.14nm) 으로 비정질 Ge의 image를 solw Scan CCD를 이용한 Elastic image를 Through Focus로 얻었으며 수치적인 정량비교를 역격자 공간에서 출발한 가장 물리적인 구조 모델을 이용하여 수행하였다. 모든 정량비교는 image의 Fourier 변환인 Diffractogram으로 하였다. 결론적으로, 많은 복잡한 수치 처리과정을 거쳐야 하지만 HRTEM의 image로부터 구조에 대한 정보(RDF)는 명확하게 얻을 수 있었다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.11a
• /
• pp.180-183
• /
• 2003

The monolayer of oxygen atoms sandwitched between the adjacent nanocrystalline silicon layers was formed by ultra high vacuum-chemical vapor deposition (UHV-CVD). This multi-layer Si-O structure forms a new type of superlattice, semiconductor-atomic superattice (SAS). According to the experimental results, high-resolution cross-sectional transmission electron microscopy (HRTEM) shows epitaxial system. Also, the current-voltage (I-V) measurement results show the stable and good insulating behavior with high breakdown voltage. It is apparent that the system may form an epitaxially grown insulating layer as possible replacement of silicon-on-insulator (SOI), a scheme investigated as future generation of high efficient and high density CMOS on SOI.

• Applied Microscopy
• /
• v.39 no.2
• /
• pp.175-183
• /
• 2009

In this paper we present sub-50 pm resolution images of atom columns simulated with the negative of the second derivative of the exit-plane wave function (EPW). The EPW can be retrieved from a focal series reconstruction in the (high resolution) transmission electron microscopy (HRTEM). The simulated images are for Si and InAs in [114] and [116] orientations, which give about sub-50 pm separations of atom columns. The theoretical reason for the validity of this method is given from analysis based on the kinematical diffraction theory, and the limitation for applicability of this method also is discussed.

• Applied Microscopy
• /
• v.38 no.1
• /
• pp.63-72
• /
• 2008

The iterative wave-function reconstruction (IWFR) method developed by Allen et al. (2004) was reviewed with concern for its applicability. The high resolution transmission electron microscopy (HRTEM) studies of the materials such as GaAs, $YBa_2Cu_3O_7$ and $Al_2CuMg$ reported in the literature were utilized in this review. In this process the basis of validity, the limiting conditions and the information limit of this method were discussed. It was particularly noted that the phase contrast image of the exit plane wave evaluated from this method reveals not only $C_s$-corrected atomic resolution within information limit, but also strong tendency of contrast proportional to the magnitude of the atomic number of compositional atoms in a crystal.

• Electronics and Telecommunications Trends
• /
• v.4 no.4
• /
• pp.98-107
• /
• 1989

실제의 결정은 이상적인 결정과는 달리 결함(imperfection or defect)들을 포함하고 있다. 본고에서는 이들 여러가지 결함들 중 격자 결함들에 국한해서, 그 기본적인 특성과 Si 격자에서의 이들 결함들의 구조를 살펴보고, 이것들을 고분해능 전자현미경(High Resolution Transmission Electron Microscopy ; HRTEM or HREM)으로 관찰했을 때, HRTEM의 탈초점 (defocus)에 따른 결함 상(image)의 성질의 변화와 함께 상 특성과 격자구조와의 관계를 살펴보았다.