• Transactions on Electrical and Electronic Materials
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• v.17 no.2
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• pp.121-124
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• 2016

ZnSnO₃ (ZTO)/Ag/ ZnSnO₃ (ZTO) trilayer films were prepared on glass substrates by radio frequency (RF) and direct current (DC) magnetron sputtering. The electrical resistivity and optical transmittance of the films were investigated as a function of the Ag interlayer thickness. ZTO films with a 15 nm thick Ag interlayer show the highest average visible transmittance (83.2%) in the visible range. In this study, the highest figure of merit (2.1×10⁻² Ω cm) is obtained with the ZTO 50 nm/Ag 15 nm/ZTO 50 nm films. The enhanced optical and electrical properties of ZTO films with a 15 nm thick Ag interlayer are attributed to the crystallization of the Ag interlayer, as supported by the distinct XRD pattern of the Ag (111) peaks. From the observed results, higher optical and electrical performance of the ZTO film with a 15 nm thick Ag interlayer seems to make a promising alternative to conventional transparent conductive ITO films.

• Journal of the Korean institute of surface engineering
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• v.54 no.3
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• pp.119-123
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• 2021

SnO₂ single layer and SnO₂/Ag/SnO₂ (SAS) tri-layered films were deposited on the glass substrate by RF and DC magnetron sputtering at room temperature and then the effect of Ag interlayer on the opto-electrical performance of the films were considered. As deposited SnO₂ films show a visible transmittance of 85.5 % and a sheet resistance of 1.2×10⁴ Ω/□, the SAS films with a 15 nm thick Ag interlayer show a lower resistance of 18.8 Ω/□ and a visible transmittance of 70.6 %, respectively. The figure of merit based on the optical transmittance and sheet resistance revealed that the Ag interlayer in the SnO₂ films enhances the opto-electrical performance without substrate heating or annealing process.

• Korean Journal of Materials Research
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• v.21 no.10
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• pp.546-549
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• 2011

Nano-sized $SnO_2$ thick films were prepared by a screen-printing method onto $Al_2O_3$ substrates. The sensing characteristics were investigated by measuring the electrical resistance of each sensor in a test box as a function of the detection gas. The nano-sized $SnO_2$ thick film sensors were treated in a $N_2$ atmosphere. The structural properties of the nano $SnO_2$with a rutile structure according to XRD showed a (110) dominant $SnO_2$ peak. The particle size of $SnO_2$:Ni nano powders at Ni 8 wt% was about 45 nm, and the $SnO_2$ particles were found to contain many pores according to the SEM analysis. The sensitivity of the nano $SnO_2$-based sensors was measured for 5 ppm $CH_4$ gas and $CH_3CH_2CH_3$ gas at room temperature by comparing the resistance in air with that in the target gases. The results showed that the best sensitivity of $SnO_2$:Ni and $SnO_2$:Co sensors for $CH_4$ gas and $CH_3CH_2CH_3$ gas at room temperature was observed in $SnO_2$:Ni sensors doped with 8 wt% Ni. The response time of the $SnO_2$:Ni gas sensors was 10 seconds and recovery time was 15 seconds for the $CH_4$ and $CH_3CH_2CH_3$ gases.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.03a
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• pp.190-190
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• 2003

여러원소 (Sb, F 등)를 도핑한 SnO$_2$ 투명전도막은 여러 가지 훌륭한 특성으로 Solar cell, heat mirrors, gas sensors, liquid crystal displays, thick film resistor 등과 같이 넓은 범위에서 응용되고 있다. 본 연구에서는 Sb 도핑된 Tin Oxide films이 Sol-gel dip coating법에 의해 준비되었다. SnO$_2$:Sb 용액은 SnC1$_2$ 와 SbC1$_3$ Power를 알코올에 용해하여 Ethylene glycol 와 Citric acid를 첨가하여 합성하였다. 막의 상형성은 XRD와 SEM(Scanning electron microscope)에 의해서 분석되었으며, 특성분석은 투과율(UV/VIS Spectrophotometer)과 표면전기저항(four point probe)으로 분석되었다. SiO$_2$ barrier이 SnO$_2$:Sb 막의 특성에 미치는 영향을 확인하기 위하여 XPS(X-ray photoelectron spectroscopy) 분석이 적용되었다.

• Progress in Superconductivity and Cryogenics
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• v.19 no.3
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• pp.18-22
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• 2017

Addition of $BaSnO_3$ (BSO) to $GdBa_2Cu_3O_{7-{\delta}}$ (GdBCO) is reported to enhance the flux pinning property of GdBCO thick films. To investigate the effect of growth condition on the pinning properties, 700 nm-thick BSO-added GdBCO films deposited with varying temperatures and growth rates were prepared by using a pulsed laser deposition method. As the deposition temperature increases, the critical current density and the pinning force density show an improved field dependence up to $750^{\circ}C$ due to the increase in the formation of the a-axis growth and the BSO nanostructures. The films deposited at higher temperatures show degraded surfaces and as a result, degraded pinning behaviors. For the change in growth rate, the critical current density and the pinning force increase as the repetition rate increase at low magnetic fields, but this behavior is reversed in high magnetic fields. These results indicate that the film growth conditions significantly affect the formation of BSO nanostructures and the pinning properties of BSO-added GdBCO films.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.8
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• pp.622-626
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• 2010

Cu doped $SnO_2$ thick films for gas sensors were fabricated by screen printing method on alumina substrates and annealed at $500^{\circ}C$ in air, respectively. Structural properties of $SnO_2$ by X-ray diffraction showed (110), (101) and (211) dominant tetragonal phase. The effects of catalyst Cu in $SnO_2$-based gas sensors were investigated. Sensitivity of $SnO_2$:Cu sensors to 2,000 ppm $CO_2$ gas and 50 ppm $H_2S$ gas was investigated for various Cu concentration. The highest sensitivity to $CO_2$ gas and $H_2S$ gas of Cu doped $SnO_2$ gas sensors was observed at the 8 wt% and 12 wt% Cu concentration, respectively. The improved sensitivity in the Cu doped $SnO_2$ gas sensors was explained by decrease of electron depletion region in Cu and $SnO_2$ junction, and increase of reactive oxygen and surface area in the $SnO_2$.

• Bulletin of the Korean Chemical Society
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• v.32 no.6
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• pp.1865-1872
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• 2011

This study investigates the sensitivity of a gas sensor to volatile organic compounds (VOCs) at various operating temperatures and catalysts. Nano-sized powdered $WO_3$ prepared by sol-gel and chemical precipitation methods was mixed with various metal oxides. Next, transition metals (Pt, Ru, Pd, and In) were doped on the surface of the mixture. Metal-$WO_3$ thick films were prepared using the screen-printing method. The physical and chemical properties of the films were studied by SEM/EDS, XRD, and BET techniques. The measured sensitivity to VOCs is defined as the ratio ($R_a/R_g$) of resistance ($R_{air}$) of $WO_3$ film in the air to resistance ($R_{gas}$) of $WO_3$ film in a VOCs test gas. The sensitivity and selectivity of the films were tested with various VOCs such as acetaldehyde, formaldehyde, methyl alcohol, and BTEX. The thick $WO_3$ film containing 1 wt % of Ru and 5 wt % of $SnO_2$ showed the best sensitivity and selectivity to acetaldehyde gas at an operating temperature of 300 $^{\circ}C$.

• Journal of the Korean Institute of Gas
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• v.11 no.1 s.34
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• pp.29-33
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• 2007

This study investigates the use of $TiO_{2},\;Pd,\;Pt$, and In which greatly improves a sensitivity to trimethylamine gas. The metal-$SnO_{2}$ thick films were prepared by screen-printing method onto $Al_{2}O_{3}$ substrates with platinum electrode. The sensing characteristics were investigated by measuring the electrical resistance of each sensor in a test box as a function of detecting gas concentration. This was then used to detect trimethylamine, dimethylamine, and ammonia vapours within the concentration range of 100-1000ppm. The gas sensing properties of metal-$SnO_{2}$ mixed thick films depended on the content and variety of metal. It was found that sensitivity and selectivity of the films dopped with 1 wt% Pd and 10 wt% $TiO_{2}$ for trimethylamin gas showed the best result at $250^{\circ}C$.

• Journal of Information Display
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• v.2 no.1
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• pp.38-42
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• 2001

Thin films of $In_2O_3-SnO_2$(ITO), $SnO_2$, and $SiO_2$ were prepared on the PET substrate by DC magnetron roll sputtering. 135 nm thick ITO film on $SiO_2$/PET substrate has sheet resistance as low as 55 ${\Omega}/square$ and transmittance as high as 85%. $H_2O$gas permeation through the film was 0.35 g/$m^2$ in a day. These properties are enough on optical film for the plastic LCD substrate or touch panel. Both refractive index and sheet resistance of ITO was found to be very sensitive to $O_2$ flow rate. Oxygen flow conditions have been optimized from 4 to 5 SCCM at $10^{-3}$torr. It is also shown that both thickness of $SnO_2$ and refractive index of $SiO_2$ decrease as $O_2$ flow rate increases.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.3
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• pp.228-233
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• 2007

Core technologies for integrating hydrogen gas sensor were investigated. In this study, the thermally isolated micro-hot-plate with areas of $100{\times}100-260{\times}260{\mu}m^2$ was fabricated by utilizing surface micromachining technique that provides better manufacturing yield than bulk micromachining counterpart. The optimum design of the sensor was peformed by analyzing the thermal profile of the structure obtained from a ANSYS simulator. The 400-nm-thick polysilicon films doped with phosphorus, the 300-nm-thick aluminum films, and the 200-nm-thick $SnO_2$(or ZnO)films were used as the micro-heater material, the temperature sensor material, and the gas sensitive material, respectively. The experimental results show that the developed gas sensors can detect $H_2$ concentration as low as 1 ppm.