• Korean Journal of Materials Research
• /
• v.18 no.12
• /
• pp.669-672
• /
• 2008

Well-aligned Zinc oxide (ZnO) nanowires were synthesized on silicon substrates by a carbothermal evaporation method using a mixture of ZnO and graphite powder with Au thin film was used as a catalyst. The XRD results showed that as-prepared product is the hexagonal wurzite ZnO nanostructure and SEM images demonstrated that ZnO nanowires had been grown along the [0001] direction with hexagonal cross section. As-grown ZnO nanowires were coated with glucose oxidase (GOx) for glucose sensing. Glucose converted into gluconic acid by reaction with GOx and two electrons are generated. They transfer into ZnO nanowires due to the electric force between electrons and the positively charged ZnO nanostructures in PBS. Photoluminescence (PL) spectroscopy was employed for investigating the movements of electrons, and the peak PL intensity increased with the glucose concentration and became saturated when the glucose concentration is above 10 mM. These results demonstrate that ZnO nanostructures have potential applications in biosensors.

• Proceedings of the KIEE Conference
• /
• 2004.07c
• /
• pp.1570-1572
• /
• 2004

OLED(organic light-emitting diode)소자에 사용되는 ITO(Indium-tin oxide)전극에 Ar/$O_3$ 플라즈마 표면처리 함으로써 ITO전극에 표면상태의 개선에 좋은 영향을 미치는 것으로 나타났다. 13.56MHZ RF 플라즈마 장치를 이용하여 Ar/$O_3$ 플라즈마 처리한 후 AFM(atomic force microscopy)측정을 통해 표면 morphologyjroughless를 분석하고, XPS(X-Ray Photoelectron Spectroscopy)분석을 통해 표면의 화학적 조성비 분석을 수행 하였다.

• Bulletin of the Korean Chemical Society
• /
• v.31 no.2
• /
• pp.397-400
• /
• 2010

Zirconium oxide thin films deposited on the p-type Si(100) substrates by radio-frequency (RF) reactive magnetron sputtering with different plasma gas ratios have been studied by using spectroscopic ellipsometry (SE), atomic force microscopy (AFM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The deposition of the films was monitored by the oxygen gas ratio which has been increased from 0 to 80%. We found that the thickness and roughness of the zirconium oxide thin films are relatively constant. The XRD revealed that the deposited thin films have polycrystalline phases, Zr(101) and monoclinic $ZrO_2$ ($\bar{1}31$). The XPS result showed that the oxidation states of zirconium suboxides were changed to zirconia form with increasing $O_2$ gas ratio.

• Transactions on Electrical and Electronic Materials
• /
• v.17 no.6
• /
• pp.355-358
• /
• 2016

We present the alignment characteristics of LC (liquid crystal) molecules on solution-derived HLO (hafnium lanthanum oxide) films fabricated using IB (ion-beam) irradiation. We then demonstrated that LC molecules can be homogeneously and uniformly aligned on the HLO film irradiated at an IB incident energy of 1.2 keV. Physicochemical analysis methods such as atomic force microscopy and X-ray photoelectron spectroscopy were used to verify the LC alignment mechanism on the IB-irradiated HLO film. In addition, the electro-optical performance of a TN (twisted-nematic) cell fabricated using the IB-irradiated HLO film exhibited characteristics superior to those of the conventional TN cell fabricated using a rubbed polyimide layer.

• Journal of the Korean Society for Heat Treatment
• /
• v.28 no.1
• /
• pp.7-16
• /
• 2015

The fabrication of high quality graphene using chemical vapor deposition (CVD) method for application in semiconductor, display and transparent electrodes is investigated. Temperature and pressure have major impact on the growth of graphene. Graphene doping was obtained by deposition of $MoO_3$ thin films using thermal evaporator. Bilayer graphene and the metal layer graphene were obtained. According to the behavior of graphene growth P-type doping was confirmed. Graphene obtained through experiments was analyzed using optical microscopy, Raman spectroscopy, UV-visible light spectrophotometer, 4-point probe sheet resistance meter and atomic force microscopy.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.18 no.8
• /
• pp.734-739
• /
• 2005

Zinc oxide films were deposited on Si (111) substrates by radio-frequency (rf)sputtering at a room temperature and post annealed in Na, air, and $H_2O$ ambient at temperatures between $800{\circ}C$ for 2 hrs. The properties were investigated by atomic force microscope (AFM), X-ray diffraction (XRD), Auger electron spectroscopy (AES) and photoluminescence (PL). Our experiments demonstrated that ZnO films have the better crystal quality for post thermal annealing and especially in $H_2O$ ambient. Even though thermal annealing reduced deep level emission somewhat, for further getting rid off deep level emission, oxygen contents should be adjusted. In our results, $H_2O$ ambient gave the best structural and optical properties.

• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.52 no.6
• /
• pp.261-266
• /
• 2003

We investigated the effect of oxygen plasma treatment of indium-tin oxide(ITO) surface on the performance of electroluminescence(EL) devices. ITO surface treated oxygen plasma has been analyzed using atomic force microscope(AFM) and X-ray photoelectron spectroscopy(XPS), to investigate the relations between the properties of the ITO surface and the properties of the current-voltage-luminance(I-V-L) characteristics of the fabricated OLED with the structure of ITO(plasma treatment) / TPD / Alq$_3$/ Al. It is found that the oxygen plasma treatment of ITO anode improve the hole injection of the OLED due to the modification of the surface states. The treated ITO anode nay be low voltage with high luminance efficiency.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2002.05a
• /
• pp.188-191
• /
• 2002

3-D orthogonal woven carbon/Al composites were fabricated using a pressure infiltration casting method. Especially, to minimize geometrical deformation of fiber pattern and $Al_4C_3$ formation, the process parameters of the minimum pressurizing force, melting temperature, delay and holding time of molten aluminum pressurizing was optimized through the PC-controlled monitoring system. Resonant ultrasound spectroscopy (RUS) was utilized to measure the effective elastic constants of 3-D orthogonal woven carbon/Al composites. The CTE measurement was conducted using strain gages in a heating oven.

• Journal of Hydrogen and New Energy
• /
• v.25 no.3
• /
• pp.305-310
• /
• 2014

This study examined the morphological changes in lithium surface immersed in 1mol $dm^{-3}$ (M) $LiPF_6 $ dissolved in propylene carbonate (PC) containing different 1,2-dimethoxyethane (DME) concentrations as a co-solvent. A passivation film was formed on the surface of lithium metal by electrolyte decomposition. The passivation film formation reactions were significantly affected by the amount of co-solvent, DME, in electrolyte solution. A stable film was obtained from the 1 M $LiPF_6 $ / PC:DME (67:33) solution in which lithium electrode showed good electrochemical performances. Atomic force microscope (AFM) and electrochemical impedance spectroscopy (EIS) results revealed that there were no direct correlations between changes in the surface morphology of lithium metal and the resistance behavior of its passivation film.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2004.04a
• /
• pp.175-176
• /
• 2004

To develope of efficient method for decontaminating of lead ions from industrial wastewater, treatment of aqueous lead solution with magnetic beads was investigated. Immobilization of carboxyl groups on tile surface of magnetic beads was carried out to introduce chelate effect between lead ions and beads. Experiments were performed with lead solutions and magnetic beads at pH 6. Lead ions were extracted during 1 hour, After extraction, magnetic beads were separated from water by outer magnetic force and the solution was analysed by atomic absorption spectroscopy (AAS). Over 90 % of lead ions could be removed from aqueous solution after beads application. This result indicate that magnetic beads can be used as a efficient method for removing lead ions from industrial wastewater.