• Journal of the Semiconductor & Display Technology
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• v.6 no.4
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• pp.29-32
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• 2007

Zinc gallate, $ZnGa_2O_4:Mn^{2+}$ co-doped with different concentrations of $Mg^{2+}$ (0.001- 0.5 mol%) was prepared by solid state synthesis method. These compositions were investigated for their photoluminescence and cathodoluminescence properties. The optimized composition $Zn_{0.990}Mg_{0.005}Ga_2O_4:Mn_{0.005}$ shows higher luminescence intensity compared to the parent phosphor. The intense green emission peak was found at 504 nm. The $Mg^{2+}$ doping does not affect much the decay time. It remains <10 ms for these compositions which make them potential candidate for application in TV screens.

• 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.

• Carbon letters
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• v.10 no.2
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• pp.123-130
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• 2009

Multi-elements doped $TiO_2$ was prepared as a new photocatalyst in order to decrease the band gap of $TiO_2$ by sol-gel process which can provide the large active sites of $TiO_2$. Multi-elements were doped by using a single precursor, tetraethylammonium tetrafluoroborate (TEATFB). By the benefit of large specific surface area of $TiO_2$ prepared by sol-gel process, catalysts showed initial fast removal of dye. The photoactivity showed that the doped catalysts significantly promote the light reactivity than undoped $TiO_2$. The commendable photoactivity of prepared catalysts is predominantly attributable to the doping of anions which may reduce the band gap.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.34 no.5
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• pp.186-192
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• 1985

Co2O3 additive effects on the electrical properties in ZnO varistor are investigated. As the Co Cations being substituted and ionized normally to a divalent state for Zn in the lattice site increase, the leakage current in the prebreakdown region decreases and the so-called

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.17 no.1
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• pp.35-40
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• 2007

Cobalt ($Co^{2+}$) doped yttria stabilized cubic zirconia (YSZ, $Y_2O_3\;:\;25{\sim}50wt%$) single crystals grown by a skull melting method were heat-treated in $N_2\;at\;1000^{\circ}C$ for 5 hrs. The reddish brown single crystals were changed into either violet or blue color, respectively. Before and after heat treatment, the Co-doped YSZ crystals cut for wafers (${\phi}6.5{\times}t\;2mm$) and round brilliant (${\phi}10mm$). The optical and structural properties were examined by UV-VIS spectrophotometer and XRD. These results are analyzed absorption by $Co^{2+}\;(^4A_2(^4F)\to{^4P})\;and\;Co^{3+}$, change of energy gap and lattice parameter.

• Transactions of the Society of Information Storage Systems
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• v.1 no.1
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• pp.93-98
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• 2005

Rewritable optical disk is one of the essential data storage media in these days, which takes advantage of the different optical properties in the amorphous and crystalline states of phase change materials. As well known, data transfer rate is one of the most important parameter of the phase change optical disks, which is mostly limited by the crystallization speed of recording media. Therefore, we doped Sn/Bi to $Ge_2Sb_2Te_5$ alloy in order to improve the crystallization speed and investigated the dependence of phase change characteristics on Sn/Bi doping concentration. The Sn/Bi doped $Ge_2Sb_2Te_5$ thin film was deposited by RF magnetron co-sputtering system and phase change characteristics were investigated by X-ray diffraction (XRD), static tester, UV-visible spectrophotometer, electron probe microanalysis (EPMA), inductively coupled plasma mass spectrometer (ICP-MS) and atomic force microscopy (AFM). Optimum doping concentration of Bi and Sn were 5${\~}$6 at.$\%$ and the minimum time for crystallization was below than 20 ns. This improvement is correlated with the simple crystalline structure of Sn/Bi doped $Ge_2Sb_2Te_5$ and the reduced activation barrier arising from Sn/Bi doping. The results indicate that Sn/Bi might play an important role in the transformation kinetics of phase change materials..

• Proceedings of the Korean Magnestics Society Conference
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• 2007.05a
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• pp.47.1-47.1
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• 2007

• Proceedings of the Materials Research Society of Korea Conference
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• 1993.11a
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• pp.18-18
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• 1993

• Proceedings of the Korean Magnestics Society Conference
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• 2013.12a
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• pp.59-60
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• 2013

• Proceedings of the Korean Magnestics Society Conference
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• 2014.11a
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• pp.23-23
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• 2014