• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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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 $350^{\circ}C$.

• Journal of the Korean Chemical Society
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• v.24 no.3
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• pp.183-192
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• 1980

Oxidation reactions of carbon monoxide on $SnO_2$, Sb-doped $SnO_2$, and Pt catalyst were studied. The oxidation reaction was found to be first order with respect to both CO and O$_2$ on $SnO_2$ and Sb-doped $SnO_2$ catalysts, and to be of half order on Pt catalyst. A small addition of Sb to $SnO_2$ (depant composition: 0.05∼0.1 mol %) increased the rate of oxidation. On the contrary, a large addition decreased the rate. From the rate expression of oxidation on Pt catalyst, the inhibition effect of carbon monoxide on the rate of oxidation was deduced. The experimentally obtained activatio energies were 5.7 kcal for the Sb doped $SnO_2$ catalyst (dopant composion: 0.05 mole%), and 6.4 kcal for the Pt catalyst. A possible reaction mechanism was proposed from the experimentally obtained kinetic data.

• 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.

• Korean Journal of Materials Research
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• v.25 no.7
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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.

• Journal of Powder Materials
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• v.29 no.1
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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.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.7
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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.

• Korean Journal of Materials Research
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• v.23 no.11
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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 $700^{\circ}C$.

• Applied Chemistry for Engineering
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• v.21 no.4
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• pp.440-444
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• 2010

$SnO_2$ powders were prepared from the calcination of stannic acids precipitated from the aqueous solution of $SnCl_4$ with ammonium nitrate as a precipitator at $90^{\circ}C$. For the comparison of properties, the stannic acids were prepared from the homogeneous precipitation method using urea as a precipitator at the same temperature. The stannic acid from ammonium nitrate at a thermal gravity analysis showed the weight loss until $700^{\circ}C$ and the percentage of total weight loss was 16.5%. The crystallization of stannic acid into $SnO_2$ finished in the calcination at $600^{\circ}C$ for 2 h. The crystallite size of $SnO_2$ increased with the increase of calcination temperature and initial concentration of $SnCl_4$ solution. In case of the same calcination condition, $SnO_2$ prepared from homogeneous precipitation using urea had a relatively smaller crystallite size rather than $SnO_2$ prepared from ammonium nitrate.

• ETRI Journal
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• v.37 no.6
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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.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.2
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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 $0.17{\times}10^{-3}{\Omega}^{-1}$.