• Korean Journal of Materials Research
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• v.20 no.8
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• pp.408-411
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• 2010

Indium doped $SnO_2$ thick films for gas sensors were fabricated by a screen printing method on alumina substrates. The effects of indium concentration on the structural and morphological properties of the $SnO_2$ were investigated by X-ray diffraction and Scanning Electron Microscope. The structural properties of the $SnO_2$:In by X-ray diffraction showed a (110) dominant $SnO_2$ peak. The size of $SnO_2$ particles ranged from 0.05 to $0.1\;{\mu}m$, and $SnO_2$ particles were found to contain many pores, according to the SEM analysis. The thickness of the indium-doped $SnO_2$ thick films for gas sensors was about $20\;{\mu}m$, as confirmed by cross sectional SEM image. Sensitivity of the $SnO_2$:In gas sensor to 2000 ppm of $CO_2$ gas and 50 ppm of H2S gas was investigated for various indium concentrations. The highest sensitivity to $CO_2$ gas and H2S gas of the indium-doped $SnO_2$ thick films was observed at the 8 wt% and 4 wt% indium concentration, respectively. The good sensing performances of indium-doped $SnO_2$ gas sensors to $CO_2$ gas were attributed to the increase of oxygen vacancies and surface area in the $SnO_2$:In. The $SnO_2$:In gas sensors showed good selectivity to $CO_2$ gas.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.5-6
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• 2009

In this paper, plasma ion implant is performed with $PH_3$ gas diluted by helium gas on P-type Si wafer (100). Spike Rapid Thermal Processing(RTP) annealing performed for 30~60 sec from $800\;^{\circ}C$ to $1000\;^{\circ}C$ in $N_2+O_2$ ambient. Crystalline defect is analyzed by Transmission Electron Microscope(TEM) and Double crystal X-ray Diffraction(DXRD). Contact resistivity($\rho c$), contact resistance(Rc) and sheet resistance(Rs) are analyzed by measuring Transfer Length Method(TLM) using 4155C analysis. As annealing temperature increase, Rs decrease and ${\rho}c$ and Rc increase at temperature higher than $850\;^{\circ}C$. We achieve low Rs, ${\rho}c$ and Rc with Plasma ion implant and spike RTP.

• Proceedings of the KIEE Conference
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• 1991.11a
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• pp.261-264
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• 1991

Titanium carbide(TiC) films were deposited on stainless-steel sheets using HCD(Hollow Cathode Discharge) reactive ion plating. Acetylene gas was used as the reactant gas. The characteristics of TiC films were examined by X-Ray diffraction, $\alpha$-step, ESCA(Electron Spectroscopy for Chemical Analysis), and, AES(Auger Electron Spectroscopy). The results were discussed with regard to various deposition conditions(bias voltage, acetylene flow rate, temperature).

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.1
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• pp.48-53
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• 2001

The crystal structure of ZnS fabricated by gas-liquid phase reaction was refined by the Rietveld program using X-ray diffraction data. The R-weighted pattern (R$\sub$wp/) of ZnS powder was 10.85%. The fraction of HCP phase was closely related with extra amount of H$_2$S gas. The lattice parameters and crystalline size were changed by the relative ratio of multi-phase. The luminescence property of ZnS:Cu, Al green phosphors prepared by conventional methods was good in the range of 91∼94% and 150∼190${\AA}$, respectively. According to the maximum entropy electron density(MEED) methods, any defects in (001) plane of cubic phase were not found. We suggest that both the Rietveld and maximum entropy density methods may be useful tools for studying luminescence mechanism of other phosphors materials.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.384-384
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• 2010

Zirconium oxynitride films were obtained by r.f. reactive magnetron sputtering of a zirconium target with nitrogen flow rate ranging from 0 to 60 sccm. The phases present in the films were determined by X-ray diffraction (XRD). Measurements of the oxidation state $ZrON_x$ films were investigated by X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). Thickness of these samples was estimated by spectroscopic ellipsometry (SE) and scanning electron microscopy (SEM). We found that the surface morphology of $ZrON_x$ films measured by atomic force microscopy (AFM) was also depended on the nitrogen gas flow.

• Resources Recycling
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• v.13 no.5
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• pp.45-50
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• 2004

To investigate the characteristics of phases formed in iron carbides, super iron carbide was synthesized from hematite fines with $CO-H_2$ gas mixture after reduction under $H_2$ gas at $600^{\circ}C$. Before carburization, the surface of iron powder reduced was pre-treated in the atmosphere of 0.05 vol% $NH_3$-Ar. The synthesized iron carbides were comprehensively explored by C/S analyzer(Low C/S determinator), M$\"{o}$ssbauer spectroscopy, X-ray diffraction patterns(XRD), scanning electron microscopy(SEM), transmission electron microscopy(TEM), and Raman spectroscopy at various reaction time of 5, 10, 15, 20, 25, 30, and 35 min, respectively. By adding a small amount of $NH_3$ gas, the super iron carbides containing 10 wt% carbon were synthesized, and its addition stabilized iron carbides. It was found that the $NH_3$ treatment played a major role in the formation of iron carbide without decomposition($Fe_3C{\to}$3Fe+C) of iron carbides and precipitation of free carbon. It also succeed to synthesize super iron carbide, $Fe_5C_2$, as a stable single phase without involving Fe and $Fe_3C$ phases.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.173.2-173.2
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• 2014

Thin nitride thin films were synthesized by reactive radio-frequency magnetron sputtering in the ultra high vacuum (UHV) chamber. To control the characteristics of thin films, tin nitride thin films were obtained various argon and nitrogen gas mixtures, especially low nitrogen gas ratios. Tin nitride thin films were analyzed with alpha step, scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and 4 point probe measurement. The result of alpha step and SEM showed that the thickness of thin nitride thin films were decreased with increasing nitrogen gas ratios. The metallic tin structure was decreased and the amorphous tin nitride structure were observed by XRD with higher nitrogen gas ratios. The oxidation state of tin and nitride were studied with high resolution Sn 3d and N 1s XP spectra.

• Transactions on Electrical and Electronic Materials
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• v.17 no.3
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• pp.146-149
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• 2016

The CrN/TiN/Al thin films for solar selective absorber were prepared by dc reactive magnetron sputtering with multi targets. The binary nitride CrN layer deposited with change in N₂ gas flow rates. The gas mixture of Ar and N2 was an important parameter during sputtering deposition because the metal volume fraction (MVF) was controlled by the N2 gas flow rate. In this study, the crystallinity and surface properties of the CrN/TiN/Al thin films were estimated by X-ray diffraction (XRD), atomic force microscopy (AFM) and field emission scanning electron microscopy (FESEM). The composition and depth profile of thin films were investigated using Auger electron spectroscopy (AES). The absorptance and reflectance with wavelength spectrum were recorded by UV-Vis-NIR spectrophotometry at a range of 300~1,100 nm.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.315.2-315.2
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• 2014

Pt-functionalized ZnS nanowires were synthesized on Au-deposited c-plane sapphire substrates by thermal evaporation of ZnS powders followed by wet Pt coating and annealing. The $NO_2$ gas sensing properties of multiple-networked Pt-functionalized ZnS nanowire sensors were examined. Scanning electron microscopy showed the nanowires with diameters of 20-80 nm. Transmission electron microscopy and X-ray diffraction showed that the nanowires were wurtzite-structured ZnS single crystals. The Pt-functionalized ZnS nanowire sensors showed enhanced sensing performance to $NO_2$ gas at $150^{\circ}C$ compared to pristine ZnS nanowire sensors. Pristine and Pt-functionalized ZnS nanowire sensors showed responses of 140-211% and 207-488%, respectively, to 1-5 ppm $NO_2$, which are better than or comparable to those of many oxide semiconductor sensors. In addition, the underlying mechanism of the enhancement of the sensing properties of ZnS nanowires by Pt functionalization is discussed.

• Journal of the Korean institute of surface engineering
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• v.48 no.5
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• pp.238-244
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• 2015

$TiO_2$ nanowires were synthesized by hydrothermal method for the application to ethanol gas sensor. $TiO_2$ nanowires were decorated with Au nanoparticles to improve the sensitivity to ethanol gas. Scanning electron microscopy and Transmission electron microscopy revealed that the synthesized nanowires had diameters and lengths of approximately 100 - 200 nm and a few micrometers, respectively. Size of the Au nanoparticles decorated on the $TiO_2$ nanowires was observed to be in the range of 10 - 20 nm. X-ray diffraction confirmed that the decorated nanowires were composed of anatase-, rutile-$TiO_2$, and Au. The sensitivities of $TiO_2$ nanowires sensors decorated with Au were approximately 1.1 - 3.65 times as high as those of as-synthesized $TiO_2$ sensors for the ethanol concentration of 5 - 100 ppm at $200^{\circ}C$. The mechanism of the improved ethanol gas sensing of the $TiO_2$ nanowires decorated with Au nanoparticles is discussed.