• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
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• pp.865-868
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• 2002

$SnO_2$ powders were prepare by precipitating $Sn(OH)_4$ from an aqueous solution of $SnCl_4{\cdot}5H_2O$, pH 9.5. The effects of stability and sensitivity of $SnO_2$ thick film sensors added with various amounts, $SiO_2$, $Al_2O_3$, $ZrO_2$, $TiO_2$ have been investigated. It is shown that the 3wt% $Al_2O_3$ or $SiO_2$ can improve the stability of $SnO_2$ gas sensor at an operating temperature of $350^{\circ}C$.

• 대한화학회지
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• 제24권3호
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• pp.183-192
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• 1980

$SnO_2$, Sb-doped $SnO_2$>, 그리고 백금촉매하에서 일산화탄소의 산화반응을 연구하였다. $SnO_2$ 및 Sb-doped $SnO_2$ 촉매하에서 산화반응은 CO 및 $O_2$에 대해서 각각 1차, 백금 촉매하에서는 1/2차 반응에 따랐다. $SnO_2$에 소량의 Sb첨가(dopant composition : 0.05∼0.1mole%)는 반응속도를 증가시키고 그 이상의 첨가는 오히려 반응속도를 감소시켰다. 백금 촉매하의 산화반응에서는 일산화탄소의 농도가 증가함에 따라 반응속도가 오히려 감소하는 억제효과를 보여주었다. 각 촉매하에서 산화반응의 활성화에너지는 Sb-dopoped $SnO_2$ 촉매 (dopant compisito : 0.05 mole%)에서 5.7 kcal, 백금 촉매에서 6.4 kcal이었다. 실험적으로 얻은 반응차수와 doping 효과로부터 가능한 반응메카니즘을 제안하였다.

• 한국재료학회지
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• 제21권10호
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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.

• 한국재료학회지
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• 제25권7호
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• pp.347-351
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• 2015

To study the characteristics of ZTO, which is made using a target mixed $ZnO:SnO_2=1:1$, the ZnO and $SnO_2$ were analyzed using PL, XRD patterns, and electrical properties. Resulting characteristics were compared with the electrical characteristics of ZnO, $SnO_2$, and ZTO. The electrical characteristics of ZTO were found to improve with increasing of the annealing temperature due to the high degree of crystal structures at high temperature. The crystal structure of $SnO_2$ was also found to increase with increasing temperatures. So, the structure of ZTO was found to be affected by the annealing temperature and the molecules of $SnO_2$; the optical property of ZTO was similar to that of ZnO. Among the ZTO films, ZTO annealed at the highest temperature showed the highest capacitance and Schottky contact.

• 한국분말재료학회지
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• 제29권1호
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• pp.41-46
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• 2022

In this study, we report the microstructure and characteristics of Ag-SnO₂-Bi₂O₃ contact materials using a controlled milling process with a subsequent compaction process. Using magnetic pulsed compaction (MPC), the milled Ag-SnO₂-Bi₂O₃ powders have been consolidated into bulk samples. The effects of the compaction conditions on the microstructure and characteristics have been investigated in detail. The nanoscale SnO₂ phase and microscale Bi2O3 phase are well-distributed homogeneously in the Ag matrix after the consolidation process. The successful consolidation of Ag-SnO₂-Bi₂O₃ contact materials was achieved by an MPC process with subsequent atmospheric sintering, after which the hardness and electrical conductivity of the Ag-SnO₂-Bi₂O₃ contact materials were found to be 62-75 HV and 52-63% IACS, respectively, which is related to the interfacial stability between the Ag matrix, the SnO₂ phase, and the Bi₂O₃ phase.

• 한국전기전자재료학회논문지
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• 제24권7호
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• pp.589-593
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• 2011

[ $SnO_2$ ]nano powders were prepared by solution reduction method using tin chloride($SnCl_2{\cdot}2H_2O$), hydrazine($N_2H_4$) and NaOH. The $SnO_2$ thick films for gas sensors were fabricated by screen printing method on alumina substrates and annealed at $300^{\circ}C$ in air, respectively. XRD patterns of the $SnO_2$ nano powders showed the tetragonal structure with (110) dominant orientation. The particle size of $SnO_2$ nano powders at the ratio of $SnCl_2:N_2H_4$+NaOH= 1:6 was about 60 nm. The sensing characteristics were investigated by measuring the electrical resistance of each sensor in a test box. Sensitivity of $SnO_2$ gas sensor to 5 ppm $CH_4$gas and 5 ppm $CH_3CH_2CH_3$ gas was investigated for various $SnCl_2:N_2H_4$+NaOH proportion. The highest sensitivity to $CH_4$ gas and $CH_3CH_2CH_3$ gas of $SnO_2$ sensors was observed at the $SnCl_2:N_2H_4$+NaOH= 1:8 and $SnCl_2:N_2H_4$+NaOH= 1:6, respectively. Response and recovery times of $SnO_2$ gas sensors prepared by $SnCl_2:N_2H_4$+NaOH= 1:6 was about 40 s and 30 s, respectively.

• 한국재료학회지
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• 제23권11호
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• pp.631-637
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• 2013

Synthesis of sub-micron $2SnO{\cdot}(H_2O)$ powders by chemical reduction process was performed at room temperature as function of viscosity of methanol solution and molecular weight of PVP (polyvinylpyrrolidone). Tin(II) 2-ethylhexanoate and sodium borohydride were used as the tin precursor and the reducing agent, respectively. Simultaneous calcination and sintering processes were additionally performed by heating the $2SnO{\cdot}(H_2O)$ powders. In the synthesis of the $2SnO{\cdot}(H_2O)$ powders, it was possible to control the powder size using different combinations of the methanol solution viscosity and the PVP molecular weight. The molecular weight of PVP particularly influenced the size of the synthesized $2SnO{\cdot}(H_2O)$ powders. A holding time of 1 hr in air at $500^{\circ}C$ sufficiently transformed the $2SnO{\cdot}(H_2O)$ into $SnO_2$ phase; however, most of the PVP (molecular weight: 1,300,000) surface-capped powders decomposed and was removed after heating for 1 h at $700^{\circ}C$. Hence, heating for 1 h at $500^{\circ}C$ made a porous $SnO_2$ film containing residual PVP, whereas dense $SnO_2$ films with no significant amount of PVP formed after heating for 1 h at $700^{\circ}C$.

• 공업화학
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• 제21권4호
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• pp.440-444
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• 2010

$SnCl_4$와 침전제로 ammonium nitrate ($NH_4NO_3$)의 수용액들을 사용하여 $90^{\circ}C$에서 침전반응으로 얻은 주석산(stannic acid)을 열처리하여 $SnO_2$ 분말을 제조하였으며, 요소($(NH_2)_2CO$)를 침전제로 사용한 균일침전법으로 주석산을 제조하여 열처리 전후로 재료의 특성을 상호 비교하였다. Ammonium nitrate의 침전법에 의한 주석산은 열처리에 따른 중량감소가 $700^{\circ}C$까지 이루어졌으며, 전체 중량감소는 16.5%였다. 또한 $600^{\circ}C$의 열처리로 비정질 주석산이 완전한 결정질의 $SnO_2$로 상변화가 이루어졌다. 주석산 제조 과정에서 $SnCl_4$ 수용액의 농도 증가 및 열처리 온도 증가에 따라 $SnO_2$의 결정입계가 증가하였다. 요소를 침전제로 사용한 균일침전법은 ammonium nitrate를 침전제로 하는 균일법보다 같은 조건의 열처리 공정 후에 상대적으로 미세한 결정입계의 $SnO_2$를 얻을 수 있었다.

• ETRI Journal
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• 제37권6호
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• pp.1135-1142
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• 2015

Multilayered ZnO-$SnO_2$ heterostructure thin films consisting of ZnO and $SnO_2$ layers are produced by alternating the pulsed laser ablation of ZnO and $SnO_2$ targets, and their structural and field-effect electronic transport properties are investigated as a function of the thickness of the ZnO and $SnO_2$ layers. The performance parameters of amorphous multilayered ZnO-$SnO_2$ heterostructure thin-film transistors (TFTs) are highly dependent on the thickness of the ZnO and $SnO_2$ layers. A highest electron mobility of $43cm^2/V{\cdot}s$, a low subthreshold swing of a 0.22 V/dec, a threshold voltage of 1 V, and a high drain current on-to-off ratio of $10^{10}$ are obtained for the amorphous multilayered ZnO(1.5nm)-$SnO_2$(1.5 nm) heterostructure TFTs, which is adequate for the operation of next-generation microelectronic devices. These results are presumed to be due to the unique electronic structure of amorphous multilayered ZnO-$SnO_2$ heterostructure film consisting of ZnO, $SnO_2$, and ZnO-$SnO_2$ interface layers.

• 한국전기전자재료학회논문지
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• 제32권2호
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• pp.134-140
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• 2019

Oxide ($SnO_2$)/metal alloy (Cu(Ni))/oxide ($SnO_2$) multilayer films were fabricated using the magnetron sputtering technique. The oxide and metal alloy were $SnO_2$ and Ni-doped Cu, respectively. The structural, optical, and electrical properties of the multilayer films were investigated using X-ray diffraction (XRD), ultraviolet-visible (UV-vis) spectrophotometry, and 4-point probe measurements, respectively. The properties of the $SnO_2/Cu(Ni)/SnO_2$ multilayer films were dependent on the thickness and Ni doping of the mid-layer film. Since Ni atoms inhibit the diffusion and aggregation of Cu atoms, the grain growth of Cu is delayed upon Ni addition. For $250^{\circ}C$, the Haccke's figure of merit (FOM) of the $SnO_2$ (30 nm)/Cu(Ni) (8 nm)/$SnO_2$ (30 nm) multilayer film was evaluated to be $0.17{\times}10^{-3}{\Omega}^{-1}$.