• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.2
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• pp.1555-1562
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• 2015

Metal oxide semiconductors have been applied in several areas, such as solar cells, sensor, optical elements and displays, due to the high surface area, unique electrical and optical characteristics. Zinc oxide among the metal oxide has excellent physicochemical properties. Zinc oxide is a n-type semiconductor with a wide direct transition band gap of 3.37 eV at room temperature and large exciton binding energy of 60 meV. Cation-doped zinc oxide studies were conducted to complement the electrical and optical characteristics. In this paper, Al-doped ZnO was synthesized by hydrothermal synthesis using microwaves. ZnO was synthesized by adjusting the precursor ratio and using different dopants. The optimal ZnO synthesis conditions for crystal shape and optical properties were determined. The optical properties of aluminum doped zinc oxide were then examined by SEM, XRD, PL, UV-vis absorbance spectrum, and EDS.

• Transactions on Electrical and Electronic Materials
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• v.16 no.2
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• pp.78-81
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• 2015

Pure ZnO and ZnO nanowires doped with 3 wt.% Ga (‘3GZO’) were grown by pulsed laser deposition in a furnace system. The doping of Ga in ZnO nanowires was analyzed by observing the optical and chemical properties of the doped nanowires. The diameter and length of nanowires were under 200 nm and several ${\mu}m$, respectively. Changes of significant resistance were observed and the sensitivities of ZnO and 3GZO nanowires were compared. The sensitivities of ZnO and 3GZO nanowire sensors measured at 300℃ for 1 ppm of ethanol gas were 97% and 48%, respectively.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.374-377
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• 2003

Sol-gel processing of BaTiO$_3$ ceramics doped with La(0.01-1.00 at.%) were prepared from metal barium, titanium n-butoxide and lanthanum isopropoxide. Characterization of the sol-gel-derived powder using XRD, SEM is also reported. The obtained results suggested that insulator to semiconductor transition for highly donor-doped barium titanate was closely related to the incorporation of donor into the grains and to the resultant grain size, which were significantly affected by the sinterability of BaTiO$_3$ powders and sintering conditions used.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1664-1667
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• 2007

The belt source evaporation is for the large size AMOLED devices to re-sublimate the organic film deposited on the metal plate. Using the plane source, the PL spectrum of the doped organic film has been studied for the first time. The PL peak of the pure Alq3 film was 512nm and that of the pure Rubrene was 557nm. The PL peak of the 2% Rubrene doped Alq3 film was shifted to $536{\pm}2nm$. The PL peak wavelength measured at the front surface of the film and at the back surface of the film was measured as nearly same as that the doping ratio maintains uniform within the film thickness. In conclusion, the doping control of the organic film becomes real using the belt type plate sublimation deposition.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.11a
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• pp.581-584
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• 2002

A new method for the preparation of lanthanide ions activated strontium aluminates phosphor by combustion method has been proposed. Combustion method consist of the redox reactions between the respective metal nitrates and urea in a preheated funace at $500^{\circ}C$. The luminescence behavior of the phosphor was studied and compared with corresponding phosphor prepared by conventional method. Effect of $Mg^{2+}$ ion concentration in strontium aluminate phosphor was investigated and the maximum luminescence of about $100cd/m^2$ was obtained. This method gave better brightness and small size to the phosphor than made by conventional method.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.1241-1242
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• 2006

Electromagnetic properties of $CeO_2$ doped and undoped YBaCuO superconductors were evaluated to investigate the effect of pinning center on the magnetization and magnetic shielding. The variation $\DeltaM$ with doping was maximum for 3% doping and decrease with further doping. The magnetic shielding was evaluated by measuring the induced voltage in secondary coil and the voltage initially set to 0.5V, decreased to 0.17V and 0.28V respectively for the undoped and 3% $CeO_2$ doped sample. The much less change in the induced voltage for the 3% doped sample is attributed to the increased flux shielding by shielding vortex current. The $CeO_2$ was converted to fine $BaCeO_3$ particles which were trapped in YBaCuO superconductor during the reaction sintering. The trapped fine particles, $BaCeO_3$ may be acted as a flux pinning center.

• Journal of information and communication convergence engineering
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• v.1 no.1
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• pp.31-34
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• 2003

Sol-gel processing of $BaTiO_{3}$ ceramics doped with La (0.01∼1.00 at.%) were prepared from metal barium, titanium n-butoxide and lanthanum isopropoxide. Characterization of the sol-gel-derived powder using XRD, SEM is also reported. The obtained results suggested that insulator to semiconductor transition for highly donor-doped barium titanate was closely related to the incorporation of donor into the grains and to the resultant grain size, which were significantly affected by the sinterability of $BaTiO_{3}$ powders and sintering conditions used.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.164-164
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• 2007

Photodiffusion of silver into chalcogenide thin film is one of the most interesting effects that occurs in chalcogenide glass as it theatrically changes the properties of the initial material and forms a ternary. Programmable Metallization Cell(PMC) Randon Access Memory use for photodiffusion of mobile metal is based on the electrochemical growth and removal of nanoscale metallic pathway in thin film of solid electrolyte. This paper investigates the annling properties on Ag-doped $Ge_{25}Se_{75}$ thin film structure and describes the electrical characteristics of PMC-RAM. The composition of the intercalation products containing Ag is confirmed using X-ray diffraction which shows the formation of Ag-doped $Ge_{25}Se_{75}$.

• Journal of the Korean institute of surface engineering
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• v.32 no.3
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• pp.244-248
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• 1999

Photoelectrodeposition of copper on semiconductive B-doped diamond films was investigated. There are cleasr morphology differences between photodeposited copper and electrodeposited copper. Photoelecrodeposition proceeded as uniform 2-dimensional growth. On the other hand electrodeposition proceeded as scarce random deposition. By applying this effect we have succeeded in forming a conductive pattern on semiconductive B-doped diamond with the aid of a photo-mask. And it was suggested that the surface reforming caused by photoelectrochemical process could be easily detected by the following metal (copper) deosition method, which is demonstrated as 'Diamond photographic phenomenon'.

• Journal of the Korean Chemical Society
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• v.42 no.6
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• pp.696-702
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• 1998

The effect of alkali metal salt on the activity of Co-Mo catalyst which has high resistance to sulfur poisoning for water gas shift reaction(WGSR) was studied. Two groups of catalysts were prepared to investigate the effects of anion and cation in alkali metal salts. For K-doped catalysts made with various potassium salts having different anion, the catalytic activity was explained to depend mainly on the BET surface area. Among the catalysts prepared by various nitrates of alkali metal as precursor, the Li-doped catalyst showed the best activity, and the others did not make significant differences giving relatively low activities. And the change of BET surface area by varying the loading of alkali metal showed a similar trend to that of activity. In this case, the activity was dependent on both BET surface area and the ratio of $Mo^{6+}$ with a tetrahedral coordination symmetry to $Mo^{6+}$ with an octahedral one, $Mo^6+[T]/Mo^{6+}[O]$ value.