• Bulletin of the Korean Chemical Society
• /
• v.32 no.5
• /
• pp.1715-1720
• /
• 2011

Nanoporous structured tin dioxide ($SnO_2$) is characterized and its application in the photocatalytic destruction of endocrine, Bisphenol A, is examined. Transmission electron microscopy (TEM) reveals irregularly shaped nanopores of size 2.0-4.5 nm. This corresponds to the result of an average nanopore distribution of 4.5 nm, as determined by Barret-Joyner-Halenda (BJH) plot from the isotherm curve. The photoluminescence (PL) curve, corresponding to the recombination between electron and hole, largely decreases in the $TiO_2$/nanoporous $SnO_2$ composite. Finally, a synergy effect between $TiO_2$ and porous $SnO_2$ is exhibited in photocatalysis: the photocatalytic destruction of Bisphenol A is improved by combining the nanoporous structured $SnO_2$ with $TiO_2$, and 75% decomposition of 10.0 ppm of Bisphenol A is achieved after 24 h.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2016.02a
• /
• pp.156.1-156.1
• /
• 2016

Nickel sulfide (NiS) is one of the most promising candidates as an electrode material for supercapacitors due to its good capacitive properties, high electrical conductivity and low cost. In addition to the development of the new electrode materials, nanostructuring the electrode surface is one of the main issues in enhancing the capacitive performance of the supercapacitors because the increased surface area can improve the charge transfer and energy storage processes occurring at the electrode surface. However, most nanofabrication techniques require complicated and delicate nanoprocesses, and hence are not suitable for practical use. In this work, we developed a simple method to fabricate nanostructured NiS electrodes by depositing NiS onto $TiO_2$ nanoparticles. First, $TiO_2$ nanoparticles were spin-coated on a fluorine-doped tin oxide (FTO) substrate, and then NiS layers were deposited onto the $TiO_2$ nanoparticles by consecutive dip-coatings in the solutions containing nickel and sulfur precursors. This nanostructured NiS electrode showed significantly improved capacitive properties compared to the electrode of NiS films deposited without $TiO_2$ nanoparticles. The asymmetric full-cell supercapacitor with this nanostructured NiS electrode and activated carbon electrode was also fabricated and investigated.

• Journal of the Korean Society for Heat Treatment
• /
• v.30 no.2
• /
• pp.61-66
• /
• 2017

$SnO_2$ was electrodeposited on nodule-type Cu foil at varing current density and electrodeposition time. Unlike the previous research results, when the anodic current is applied, the $SnO_2$ layer was not electrodeposited and the substrate is corroded. When the cathodic current was applied, the $SnO_2$ layer could be successfully deposited. At this time, the surface microstructure of the powdery type was observed, which showed similar crystallinity to amorphous and had a very large surface area. Crystallinity increased after low-temperature heat treatment at $250^{\circ}C$ or lower. As a result of evaluating the charge/discharge performances as an anode material for lithium ion battery, it was confirmed that the capacity of the heat treated $SnO_2$ was increased more than 2 times, but it still showed a limit point showing initial low coulombic efficiency and low cyclability. However, it was confirmed that the battery performances may be enhanced through optimizing the electrodeposition process and introducing post heat treatment.

• Journal of the Microelectronics and Packaging Society
• /
• v.21 no.1
• /
• pp.13-17
• /
• 2014

The direct-patternable $SnO_2$ thin film was successfully fabricated by photochemical metal-organic deposition. The composition and chemical bonding state of $SnO_2$ thin film were analyzed by using X-ray photoelectron spectroscopy (XPS) from the surface to the interface with Si substrate. XPS depth profiling analysis allowed the determination of the atomic composition in $SnO_2$ film as a function of depth through the evolution of four elements of C 1s, Si 2p, Sn 3d, and O 1s core level peaks. At the top surface, nearly stoichiometric $SnO_2$ composition (O/Sn ratio is 1.92.) was observed due to surface oxidation but deficiency of oxygen was increased to the interface of patterned $SnO_2/Si$ substrate where the O/Sn ratio was about 1.73~1.75 at the films. This O deficient state of the film may act as an n-type semiconductor and allow $SnO_2$ to be applied as a transparent electrode in optoelectronic applications.

• The Korean Journal of Nuclear Medicine
• /
• v.28 no.3
• /
• pp.326-330
• /
• 1994

A $^{82}Sr/^{82}Rb$ generator was prepared by loading $^{82}Sr$ to preconditioned tin dioxide column. The generator was eluted by normal saline with flow rate up to 8m1/min, and the eluted radioactivity was monitored by dose calibrator. Radioactivity began to come out at 5ml and reached to peak around 9ml. The total eluted radioactivity increased linearly with flow rate, and the maximum obtained radioactivity was 35mCi at 8m1/min. The $^{82}Rb$ preparation was proven to be free from both strontium radioactivity and pyrogen. The $^{82}Rb$ was injected to normal female volunteer and positron emission tomographic Image of heart was obtained successfully.

• Proceedings of the KIEE Conference
• /
• 1997.07d
• /
• pp.1352-1354
• /
• 1997

Transparent conductive thin films have found many application in many active and passive electronic and opto-electronic devices as like flat Panel display electrode and window heat mirror, etc. Low resistivity and high transmittance of this films can be obtained by controlling deposition parameters, which are oxygen partial Pressure, substrate temperature and dopant concentration. In this study, We prepared non-stoichiometric and Sb-doped thin films of tin dioxide by reactive DC magnetron sputtering technology. The lowest resistivity of about $3.0{\times}10^{-3}\;{\Omega}cm$ and 80% transmittance in the visible light region have heed obtained at optimal deposition condition.

• Journal of the Korean institute of surface engineering
• /
• v.40 no.6
• /
• pp.258-261
• /
• 2007

Relationships between the electrical resistivity and the growth characteristic of $SnO_2$ thin films were investigated. $SnO_2$ thin films with thickness from 64 nm to 91 nm were made by controlling the RF deposition energy from 80 to 150 W. These $SnO_2$ thin films were annealed at $200^{\circ}C{\sim}700^{\circ}C$ temperature range of $100^{\circ}C$ interval in the $O_2$ gas condition. After annealing treatments, the microstructures of the $SnO_2$ thin films were changed mixed structure(amorphous & crystalline) to lamina columnar crystalline structure. Both the film thickness and the grain size were increased with increasing the local crystallization of $SnO_2$ microstructure of thin films by annealing treatment. Their electrical resistivity increased up to the annealing temperature of $400^{\circ}C$, and then slowly decreased.

• Bulletin of the Korean Chemical Society
• /
• v.33 no.6
• /
• pp.1989-1992
• /
• 2012

We present a low temperature (${\approx}70^{\circ}C$) method to prepare anatase, vertically aligned feather-like $TiO_2$ (VAFT) nanowire arrays $via$ reactive pulsed DC magnetron sputtering. The synthesis method is general, offering a promising strategy for preparing crystalline nanowire metal oxide films for applications including gas sensing, photocatalysis, and 3rd generation photovoltaics. As an example application, anatase nanowire films are grown on fluorine doped tin oxide coated glass substrates and used as the photoanode in dye sensitized solar cells (DSSCs). AM1.5G power conversion efficiencies for the solar cells made of 1 ${\mu}m$ thick VAFT have reached 0.42%, which compares favorably to solar cells made of the same thickness P25 $TiO_2$ (0.35%).

• The Korean Journal of Ceramics
• /
• v.5 no.2
• /
• pp.125-130
• /
• 1999

After $SnO_2$ fine powder by precipitation method, Ca as crystallization inhibitor and Pd as catalyst were added to $SnO_2$ raw material by various methods. Thick film device was fabricated on the alumina substrate by mixing ethylene glycol and such mixed powders. The sensing characteristics of the device for methane gas were investigated. The most excellent gas sensing property was shown by the thick film device fabricated by Method 3 in which Ca and Pd doped $SnO_2$ powder is prepared by mixing $SnO_2$ powder, 0.1 wt% Ca acetate and 1 wt% $PdCl_2$ in deionized water and by calcining the mixture, after $Sn(OH)_4$ is dried at $110^{\circ}C$ for 36h. The sensitivity of the sensor fabricated with $SnO_2$-0.1 wt%Ca acetate-1wt%$PdCl_2$ powder heat-treated at $700^{\circ}C$ for 1h was about 86% for 5,000 ppm methane in air at $350^{\circ}C$ of the operating temperature. Response time and recovery were also excellent.

• Korean Journal of Materials Research
• /
• v.28 no.12
• /
• pp.758-762
• /
• 2018

The transfer characteristics of zinc tin oxide(ZTO) on silicon dioxide($SiO_2$) thin film transistor generally depend on the electrical properties of gate insulators. $SiO_2$ thin films are prepared with argon gas flow rates of 25 sccm and 30 sccm. The rate of ionization of $SiO_2$(25 sccm) decreases more than that of $SiO_2$(30 sccm), and then the generation of electrons decreases and the conductivity of $SiO_2$(25 sccm) is low. Relatively, the conductivity of $SiO_2$(30 sccm) increases because of the high rate of ionization of argon gases. Therefore, the insulating performance of $SiO_2$(25 sccm) is superior to that of $SiO_2$(30 sccm) because of the high potential barrier of $SiO_2$(25 sccm). The $ZTO/SiO_2$ transistors are prepared to research the $CO_2$ gas sensitivity. The stability of the transistor of $ZTO/SiO_2$(25 sccm) as a high insulator is superior owing to the high potential barrier. It is confirmed that the electrical properties of the insulator in transistor devices is an important factor to detect gases.