• 한국재료학회지
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• 제9권11호
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• pp.1088-1094
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• 1999

본 연구에서는 rf PECVD(13.56MHz)법을 이용하여 $CH_4$가스에 소량의 보조가스($O_2$와 $N_2$)를 혼합하여 a-C:H 박막을 얻었다. 이렇게 얻어진 박막의 증착속도는 rf power 증가에 따라서 증가하다가 200W에서는 다시 감소하였으며, 산소와 질소가스의 유량이 증가함에 따라 감소하였다. FT-IR분석으로 계산된 박막내의 수소함량은 rf power 증가와 산소 및 질소첨가량의 증가에 따라 감소하였다. 산소가스 첨가 시에는 C=O 결합이 생성되며, 질소가스 첨가 시에는 C=N 결합이 생성됨을 FT-IR 분석을 통하여 알 수 있었다. 이와 같이 산소와 질소를 보조가스로 첨가할 경우에 스퍼터링 효과로 박막내의 수소함량 감소와 더불어 a-C:H 박막의 구조 변화를 일으킬 수 있을 것으로 생각된다. Raman 분석결과 산소와 질소를 첨가함에 따라서 I(sub)D/I(sub)G비가 증가하였고, D line과 G line의 위치가 높은 파수 쪽으로 이동하였으며, D line의 폭은 넓어지는 반면에 G line의 폭은 감소됨을 보였다. 이것은 산소와 질소의 첨가로 박막내의 수소함량 감소, 결합각의 disorder 감소 및 micro-crystallite 흑연의 형성에 의한 것이라고 판단된다.

• 반도체디스플레이기술학회지
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• 제3권4호
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• pp.5-11
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• 2004

Optical properties of PET(Polyethylene terephthalate), PC(Polycarbonate), Acrylic resin and PE(Polyethylene) sheets were studied as a function of heat treating temperature of $60^{\circ}C$ to $150^{\circ}C$. By the heat treatment, optical properties of transmittance, absorbance, and reflectance showed a considerable change with different ways according to the materials. To understand the reason of optical property change, X-ray diffraction and surface morphology were also investigated. It was observed that small crystallite and pore that can cause scattering largely affect the transmittance. It was suggested that change of surface chemical bond induce the reflectance variation.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2005년도 춘계학술발표회
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• pp.411-412
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• 2005

There are some differences as a result of comparison between internal and external standard method. Thin-film XRD was used to measure the thin damaged layer by proton irradiation. Experiment was performed by external standard method to measure bulk sample accurately. A little changes of crystallite size and lattice parameter by small dose were observed. X-ray penetrates too deeply above damaged layer of graphite despite of small X-ray incident angle.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.455-455
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• 2013

$CeO_2$ nanorings were synthesized by using a surfactant free hydrothermal method. The surface morphology, structural and optical properties of the synthesized $CeO_2$ was investigated by using scanning electron microscopy (SEM), X-ray diffraction (XRD), and ultraviolet-visible (UV) spectroscopy measurements. SEM images showed that the surface morphology of the formed $CeO_2$ appeared as nanorings. The XRD pattern of $CeO_2$ nanorings showed the presence of the polycrystalline $CeO_2$ phase readily indexed to the cubic fluorite structure of the $CeO_2$. The mean crystallite size of the $CeO_2$ was calculated using the Scherrer equation from the XRD line broadening of the (111) planes of the cubic $CeO_2$. The UV-Visible spectroscopy spectrum of the $CeO_2$ nanorings exhibited a strong UV absorption band around 350 nm.

• 한국분말재료학회지
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• 제25권5호
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• pp.390-394
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• 2018

Metallic tantalum powder is manufactured by reducing tantalum oxide ($Ta_2O_5$) with magnesium gas at 1,073-1,223 K in a reactor under argon gas. The high thermodynamic stability of magnesium oxide makes the reduction reaction from tantalum oxide into tantalum powder possible. The microstructure after the reduction reaction has the form of a mixture of tantalum and magnesium oxide, and the latter could be entirely eliminated by dissolving in weak hydrochloric acid. The powder size in SEM microstructure for the tantalum powder increases after acid leaching in the range of 50-300 nm, and its internal crystallite sizes are observed to be 11.5 to 24.7 nm with increasing reduction temperatures. Moreover, the optimized reduction temperature is found to be 1,173 K as the minimum oxygen concentration is approximately 1.3 wt.%.

• 한국분말재료학회지
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• 제6권1호
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• pp.49-55
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• 1999

Al-Cr-Zr nanocomposite metal powders were prepared by mechnical alloying (MA) in order to develop aircraft structure materials with lighter weight and lower cost than the conventional Ti and Ni alloys. The morphological changes and microstrutural evolution of Al-6wt.%Cr-3wt.%Zr nanocomposite metal powders during MA were investigated by SEM, XRD and TEM. The approximately 50$\mu$m sized Al-Cr-Zr nanocomposite metal powders has been formed after 20 h of MA. The individual X-ray diffraction peaks of Al, Cr and Zr were broadened and peak intensitied were decreased as a function of MA time. The observed Al crystallite size by TEM was in the range of 20 nm, which is a simliar value calculated by Scherrer equation. The microhardness of Al-Cr-Zr nanocomposite metal powders increases alomost linearly with increase of the processing time, reaching a saturation hardness value of 127 kg/$mm^2$ after 20 h of processing. The intermetallic compound phase of $Al_3Zr_4$ in the matrix was identifed by XRD and TEM.

• 통합자연과학논문집
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• 제1권2호
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• pp.84-88
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• 2008

The formation and thermal properties of the $BaO_2$ and $TiO_2$ mixtures were prepared by mechanical alloying method was investigated by X-ray diffractometry (XRD), scanning electron microscopy (SEM), and thermogravimetric/differential thermal analysis (TG/DTA). The rotating speed of 750 rpm shows more effects on the formation of $BaTiO_3$ single phase. The internal strain calculated using Williamson-Hall method was $4.27{\times}10^{-3}$ for the mixture milled for 300 min, the crystallite size was calculated using the Scherrer method decreased with milling time. The $BaTiO_3$ crystal improved crystallinity was formed by thermal annealing at a temperature of $600^{\circ}C$ for 1 h for the mixture milled for 300 min.

• 한국세라믹학회지
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• 제25권2호
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• pp.184-190
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• 1988

ZrN powder was prepared from the powder mixture of ZrCl4 and Al by the halogenide process in nitrogen gas flow (100-150ml/min) at the temperatures from 200$^{\circ}$to 1050$^{\circ}C$. ZrN powder was formed about 600$^{\circ}C$ and in the slow nitriding reaction, however, an intermediate product of Al3Zr was formed. The fine powder (0.1-10$\mu\textrm{m}$) of single phase ZrN was obtained at 1050$^{\circ}C$ after 1 hour. The lattice parameter and crystallite size of ZrN were 4.5787A and 360A, respectively. According to SEM observation, the particles were apt to agglomerates. The apparent activation energy for the formation of ZrN was approximately 13.2kcal/mole(750$^{\circ}$-1000$^{\circ}C$).

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 C
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• pp.1485-1487
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• 2000

A variety of target configurations in sputtering process have been proposed to deposit various structures of thin film alloys and compound films. In this study, we presented the comparative experimental results regarding to the characterization of properties of Cu-Ni thin films deposited by using a magnetron co-sputtering method, as a function of target configurations; one is using a single target with varying the area of Ni chips attached on the Cu target and another is using a dual-type target with two targets of Ni and Cu separated each other. Structural(d-spacing, crystal orientation, crystallite size, cross-sectional morphology) and electrical(resistivity) properties of deposited films are characterized and compared as a function of target configurations as well as deposition conditions.

• 전기전자학회논문지
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• 제21권3호
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• pp.297-308
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• 2017

By using electron beam evaporation under appropriate conditions, we obtained graphene intercalated sheets on Si(111) with an average crystallite size less than 11nm. The formation of such nanocrystalline graphene was found as a time-dependent function of carbon deposition at a substrate temperature of $1000^{\circ}C$. The structural and electronic properties as well as the surface morphology of such produced materials have been confirmed by reflection high energy electron diffraction, Auger electron spectroscopy, X-ray photoemission spectroscopy, Raman spectroscopy, scanning electron microscopy, atomic force microscopy and scanning tunneling microscopy.