• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.357.2-357.2
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• 2014

Ruthenium (Ru) 박막은 우수한 화학적 열적 안정성 및 높은 일함수(4.7eV) 특성으로 인해 20 nm급 이하의 차세대 DRAM capacitor의 전극 물질 및 Cu metalization을 위한 seed layer로 각광을 받고 있다. Ru박막의 나노스케일 정보전자소자로의 적용을 위해서는 두께제어가 용이하고 3D 구조에서 우수한 단차 피복 특성을 갖는 atomic layer deposition (ALD)을 이용한 박막 형성이 필수적이다. 이에 본 연구에서는 ALD 방법을 이용하여 0가의(cymene) (1,5-hexadiene) Ru (0) (C16H24Ru) 전구체를 합성, ALD 방법을 이용하여 우수한 초기성장거동을 갖는 Ru 박막을 증착 하였다. 형성된 Ru 박막의 표면 형상, 두께, 밀도를 주사전자현미경(Scanning electron microscopy)과 X-선 반사율 측정(X-ray reflectometer)으로 조사하였다. 또한 전기적 특성을 4침법(four-point-probe)으로 측정하였고, 박막의 화학적 조성과 결정성의 정보를 X-선 광전자분광법(X-ray photoelectron spectroscopy)과 X-선 회절(X-ray diffraction)을 이용하여 확인하였다.

• New Physics: Sae Mulli
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• v.68 no.12
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• pp.1281-1287
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• 2018

In this study, $Al_xGa_{1-x}N$ films were grown on (0001) sapphire substrates by using metal-organic chemical vapor deposition (MOCVD). The crystallinity of the grown films was examined with X-ray diffraction (XRD) patterns. The surfaces and the chemical properties of the $Al_xGa_{1-x}N$ films were investigated using atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS), respectively. The optical properties of the $Al_xGa_{1-x}N$ film were studied in a wide photon energy range between 2.0 ~ 8.7 eV by using spectroscopic ellipsometry (SE) at room temperature. The data obtained by using SE were analyzed to find the critical points of the pseudodielectric function spectra, $<{\varepsilon}(E)>=<{\varepsilon}_1(E)>+i<{\varepsilon}_2(E)>$. In addition, the second derivative spectra, $d^2<{\varepsilon}(E)>/dE^2$, of the pseudodielectric function for the $Al_xGa_{1-x}N$ films were numerically calculated to determine the critical points (CPs), such as the $E_0$, $E_1$, and $E_2$ structure. For the four samples (x = 0.18, 0.21, 0.25, 0.29) between a composition of x = 0.18 and x = 0.29, changes in the critical points (blue-shifts) with increasing Al composition at 300 K for the $Al_xGa_{1-x}N$ film were observed via ellipsometric measurements for the first time.

• Journal of Electrochemical Science and Technology
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• v.13 no.3
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• pp.377-389
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• 2022

The current global energy supply depends heavily on fossil fuels. This makes technology such as direct water splitting from harvesting solar energy in photoelectrochemical (PEC) systems potentially attractive due to its a promising route for environmentally benign hydrogen production. In this study, undoped and nickel-doped molybdenum oxide photoanodes (called photoanodes S₁ and S₂ respectively) were synthesized through electrodeposition by applying -1.377 V vs Ag/AgCl (3 M KCl) for 3 hours on an FTO-coated glass substrate immersed in molibdatecitrate aqueous solutions at pH 9. Scanning electron microscopy (SEM), atomic force microscopy (AFM), energy-dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS) were used for microstructural and compositional characterizations of the photoanodes. In addition, the optical and photoelectrochemical characterizations of these photoanodes were performed by UV-Visible spectroscopy, and linear scanning voltammetry (LSV) respectively. The results showed that all the photoanodes produced exhibit conductivity and catalytic properties that make them attractive for water splitting application in a photoelectrochemical cell. In this context, the photoanode S₂ exhibited better photocatalytic activity than the photoanode S₁. In addition, photoanode S₂ had the lowest optical band-gap energy value (2.58 eV), which would allow better utilization of the solar spectrum.

• Ceramist
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• v.22 no.4
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• pp.368-380
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• 2019

A ceramic is used as a key material in various fields. Accordingly, the use of scanning electron microscopy is increased for the purpose of evaluating the reliability and defects of advanced ceramic materials. The scanning electron microscope is developed to overcome the limitations of optical microscopy and uses accelerated electrons for imaging. Various signals such as SE, BSE and characteristic X-rays provide useful information about the surface microstructure of specimens and, the content and distribution of chemical components. The development of electron guns, such as FEG, and the improved lens system combined with the advanced in-lens detectors and STEM-in-SEM system have expanded the applications of SEM. Automated SEM-EDS analysis also greatly increases the amount of data, enabling more statistically reliable results. In addition, X-ray CT, XRF, and WDS, which are installed in scanning electron microscope, have transformed SEM a more versatile analytical equipment. The performance and specifications of the scanning electron microscope to evaluate ceramics were reviewed and the selection criteria for SEM analysis were described.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2013.05a
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• pp.160-160
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• 2013

본 실험에서는 CIGS 흡수층을 스퍼터링 방식과 급속열처리 장비를 이용한 2-step 방식을 이용하여 형성시켰다. 전구체는 DC 스퍼터링 방법으로 $Cu_{0.75}Ga_{0.25}/In$의 다층 전구체를 구성 후, 독성이 없는 셀레늄 팰릿을 graphite 상자에 넣어 급속열처리 장비로 온도를 $475{\sim}680^{\circ}C$로 온도를 조절하면서 셀렌화 하였다. 이렇게 구성된 CIGS 흡수층의 특성을 scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray differection (XRD)를 통해서 측정을 하였다.

• Journal of the Korean Ceramic Society
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• v.49 no.2
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• pp.155-160
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• 2012

This paper reported a simple deposition-precipitation method, introducing the metal (Ni, Ag and Sn) and $Na_2S{\cdot}5H_2O$ to preparedispersion metal sulfide nanoparticles on the surface of the Multi-walled carbon nanotube for synthesis of CNT-$M_xS_y$ ($NiS_2$, $Ag_2S$, SnS) composite photocatalysts. The characterization of the prepared CNT-$M_xS_y$ ($NiS_2$, $Ag_2S$, SnS) composites was performed by X-ray diffraction, scanning electron microscopy with energy dispersive X-ray analysis and BET analysis. Furthermore, the MB degradation rate constant for CNT-SnS composite was $5.68{\times}10^{-3}$ under visible light irradiation, which was much higher than the corresponding values for other samples. The detailed formation and photocatalytic mechanism are also provided here.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2015.11a
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• pp.139-140
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• 2015

Zn/HA coating on the Ti-xNb alloys after nanotube formation for dental lmplant was researched using various experimental methods. Due to g ood biocompatibility and osteoconductivity, hydroxyapatite (HA) coating s on metallic biomedical implants were widely employed in orthopedic and dental applications. To improve biocompatibilities, Zinc (Zn) plays very important roles in the bone formation and immune reg ulations. The nanotube formed Zn-HA films were characterized with X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS).

• Applied Microscopy
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• v.30 no.3
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• pp.241-248
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• 2000

Electron microscopy has used for analysing the structure of protein over 30 years. Bacteriohodopsin and porins are used as examples to illustrate the progress that has recently been made in attaining resolutions which hitherto were regarded as exclusive to the realm of x-ray crystallography. To determine a protein structure used by electron microscopy, one must pass through a number of basic steps including preparation of specimen , data acquisition and data processing.

• Journal of the Korean Ceramic Society
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• v.40 no.1
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• pp.62-68
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• 2003

Ba-ferrite particles added with Co and Ti, which were known well the additives for the control in coercivity, were synthesized by sol-gel method. In the range 90 to 120 minute reaction time, a stable sol solution which showed no change with temperature, pH, viscosity and aging time. After dried and heat treatment of sol solution, Ba-ferrite phase formed at $700^{\circ}C$ with Differential Thermal Analysis(DTA) and X-Ray Diffractometer(XRD) measurement. The crystallinity became to be better with increasing the temperature. It were showed by Scanning Electron Microscopy(SEM) that Ba-ferrite increased to particle sizes as increasing heating temperature and obtained of narrow particles size distribution. Also, magnetic characteristics of Ba-ferrite powders Co and Ti added were observed by a Vibrating Sample Magnetometer(VSM). Saturation magnetization$(M_s)$ was not much changed, however. the coercivity$(H_c)$dramatically dropped with addition of Co and Ti.

• Journal of the Korean Vacuum Society
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• v.22 no.2
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• pp.105-110
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• 2013

Single crystalline $In_xGa_{1-x}As$ nanowires are grown on Si (111) substrate via Vapor-Liquid-Solid growth mode using metal-organic chemical vapor deposition. The ternary nanowires have been grown with various growth conditions and examined by electron microscopy. The alloy compositions of the nanowires has been investigated using Energy-dispersive X-ray spectroscopy. We have found that the composition gradient of the nanowire becomes larger with growth temperature and V/III ratio.