• 한국진공학회:학술대회논문집
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• 한국진공학회 1999년도 제17회 학술발표회 논문개요집
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• pp.74-74
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• 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.

• Applied Microscopy
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• 제34권1호
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• pp.13-21
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• 2004

최근에 한국기초과학지원연구원에 설치된 초고전압 투과전자현미경은 원자분해능(점분해능 $1.2{\AA}$ 이하)의 구현과 고경사각 tilting 기능(${\pm}60^{\circ}$)에 의해 시편의 원자배열 구조를 3차원적으로 이미징할 수 있는 고성능 투과전자현미경이다. 이에 더하여 FasTEM이라는 원격 운용 시스템이 갖춰져 있어서 장비의 직접운용에 따른 여러 제약을 극복할 수 있게 한다. 초고전압 투과전자현미경의 원격운용을 위해 FasTEM 원격 시스템은 본원 초고전압 투과전자현미경에 설치된 Server 시스템과 서울분소에 설치된 Client 콘솔 시스템을 155 Mbps급 초고속 선도망 KOREN에 연결하여 구성하였으며 서울분소에서 대전본원의 초고전압 투과전자현미경을 운영하여 Au의 [001] 고분해능 영상을 얻는데 성공하였다. 초고전압 투과전자 현미경의 조사계 및 결상계 시스템 파라메타들의 조정, 각각의 detector 시스템 조정과 이미징, goniometer와 aperture 구동을 위한 motor-driven system들의 동작 등 초고전압 투과전자현미경의 원격 조정은 원격 작업자가 현장에 있는 것과 마찬가지로 실시간 운용이 가능하였다. 초고전압 투과전자현미경과 IT 기반기술의 접목에 의해 실현된 원격운용 기능은 국가적 공동연구시설에 대한 e-Science Grid를 구축하는데 중요한 역할을 하리라 기대된다.

• Bulletin of the Korean Chemical Society
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• 제33권6호
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• pp.1949-1954
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• 2012

We have developed a novel and eco-friendly synthetic route for the preparation of a two-dimensional layered zinc hydroxide with intercalated nitrate anions. The layered zinc hydroxide nitrate, called 'zinc basic salt', was, in general, successfully synthesized, using an electron beam irradiation technique. The 2-propanol solutions containing hydrated zinc nitrate were directly irradiated with an electron-beam at room temperature, under atmospheric conditions, without stabilizers or base molecules. Under electron beam irradiation, the reactive OH radicals were generated by radiolysis of water molecules in precursor metal salts. After further radiolytic processes, the hydroxyl anions might be formed by the reaction of solvated electrons and the OH radical. Finally, the $Zn_5(OH)_8(NO_3)_2{\cdot}2H_2O$ was precipitated by the reaction of zinc cation and hydroxyl anions. Structure and morphology of obtained compounds were characterized by powder X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and high resolution transmission electron microscopy (HR-TEM). The chemical components of the products were determined by Fourier transform infrared spectroscopy (FT-IR) and elemental analysis (EA). The thermal behavior of products was studied by thermogravimetric (TG) and differential thermal analysis (DTA).

• Bulletin of the Korean Chemical Society
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• 제33권8호
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• pp.2609-2612
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• 2012

A simple green method was developed for rapid synthesis of silver and gold nanoparticles (AgNPs and AuNPs) has been reported using Lonicera japonica flower extract as a reducing and a capping agent. AgNPs and AuNPs were carried out at $70^{\circ}C$. The successful formation of AgNPs and AuNPs have been confirmed by UV-Vis spectro photometer, fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), energy dispersive X-ray Analysis (EDAX), scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). To our knowledge, this is the first report where Lonicera japonica flower was found to be a suitable plant source for the green synthesis of AgNPs and AuNPs.

• 한국세라믹학회지
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• 제55권3호
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• pp.230-238
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• 2018

Superparamagnetic iron oxide nanoparticles (SPIONs) have been prepared without using surfactants to assess their stability at different time intervals. The synthesized particles were characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, ultraviolet-visible-near infrared spectroscopy, and energy dispersive spectroscopy. Field emission scanning electron microscopy and high-resolution transmission electron microscopy images of the samples were also investigated. The average particle size was measured to be 12.7 nm even in the polydispersed form. The magnetic and dielectric characteristics of the $Fe_3O_4$ nanoparticles have also been studied and discussed in detail.

• 한국전기전자재료학회논문지
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• 제19권10호
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• pp.930-934
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• 2006

This paper reports a change of carbon nanotubes(CNTs) properties by post-treatment process after growth of CNTs. CNTs were treated by thermal method and solution method, and then investigated in detail using field emission scanning electron microscopy(FE-SEM), high resolution transmission scanning electron microscopy(HR-TEM), RAMAN spectroscopy, and Fourier Transform Infrared Spectrometer (FT-IR). FT-IR spectra showed that the amount of hydroxyl generated on surface of CNTs were changed with post-treatment condition. FE-SEM and TEM images were shown CNTs diameter and density variations were dependent with their treatment conditions. RAMAN spectroscopy was shown that carbon nanotubes structure vary with treatment conditions.

• 한국전기전자재료학회논문지
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• 제18권5호
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• pp.478-483
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• 2005

In this paper, we synthesized 10 to 20 nm diameter NiFe nanoparticles and nanoparticle films utilizing supersonic jet deposition of nanoparticle aerosols generated by laser ablation of $30\;to\;45{\mu}m$ diameter permalloy $(Ni_{81}Fe_{19} \;at\;{\%})$ microparticles. The component and composition of the nanoparticles were characterized by an energy dispersive X-ray spectroscopy. The morphology of the nanoparticles and nanoparticle films was analyzed by a high-resolution transmission electron microscopy and a scanning electron microscopy, respectively. The experimental results showed that the nanoparticles and nanoparticle films have remarkable properties with an excellent preservation of the composition of feedstock permalloy microparticles. The purpose of the present work is to present details on the composition and nanostructural characterizations for NiFe nanoparticles and nanoparticle films prepared by laser ablation of microparticles (LAM).

• 전기학회논문지
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• 제62권2호
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• pp.284-287
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• 2013

In this work, we have fabricated TiC films by using unbalanced magnetron sputtering method with graphite and Ti targets for contact strip application of electric railway. TiC films were deposited with various substrate temperatures. We investigated various properties of TiC films prepared with various substrate temperatures, such as the hardness, surface roughness, friction coefficient, resistivity, FESEM (Field Emission Scanning Electron Microscopy), HRTEM (High Resolution Transmission Electron Microscopy) and XPS (X-ray Photoelectron Spectroscopy). The hardness and friction coefficient properties of TiC films were improved with increasing substrate temperature. These results indicate that the improvement of hardness and resistivity is related to the increase of sp2 clusters in TiC films. And also, the resistivity value of TiC films were decreased with increasing substrate temperature.

• Journal of Ceramic Processing Research
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• 제13권spc1호
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• pp.154-157
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• 2012

We present the simultaneous growth of single-walled carbon nanotubes and graphene with the optimal conditions of the synthesizing parameters. The dense and vertically aligned SWNTs having the length of over 100 ㎛ was grown by 2 nm-thick Fe catalytic layer. From 650 ℃, the vertically well-grown SWNTs were obtained by increasing the temperature. The severallayered graphene was synthesized with the gas mixing ratio of 15 : 1(H2 : C2H2) at 650 ℃ and higher temperatures. With these optimal conditions, the vertically well-grown SWNTs and the several-layered graphene were synthesized simultaneously. The presence of SWNTs and the layer of graphene were verified by field emission scanning electron microscopy and high resolution transmission electron microscopy. From the result of this simultaneous synthesizing approach, the possibility of one step growth process of CNTs and grapheme could be verified.

• 전자통신동향분석
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• 제4권4호
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• pp.98-107
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• 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.