• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.11-11
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• 2007

1차원 구조체인 반도체 나노선은 앙자제한효과 (quantum confinement effect) 등을 이용하여 고밀도/고효율의 소자 개발이 기대되고 있다. GaN는 상온에서 3.4 eV의 밴드갭 에너지를 갖는 III-V 족 반도체 재료로써 박막의 경우 광전자 소자로 폭넓게 응용되고 있다. 최근 GaN 나노선의 합성에 성공하면서 발광소자, 고효율의 태양전지, HEMT 등으로의 응용을 위한 많은 연구가 활발히 이루어지고 있다. 하지만, 아직까지 GaN 나노선의 전기적 특성을 제어하는 기술은 확립되지 않고 있다. 본 연구에서는 Vapor solid (VS)법을 이용하여 GaN 나노선을 합성하였으며, GaN 분말과 함께 $Mg_2N_3$ 분말을 첨가하여 (Ga,Mg)N 나노선을 성공적으로 합성하였다. 합성시에 GaN와 Mg 소스간의 거리 변화를 통해 Mg 도핑농도를 제어하고자 하였다. 이 같은 방법으로 합 된 (Ga,Mg)N 나노선의 Mg 도핑농도에 따른 결정학적 특성을 알아보고, (Ga,Mg)N 나노선을 이용하여 소자를 제작한 후 그 전기적 특성을 살펴보고자 한다. X-ray diffraction (XRD)과 high-resolution transmission electron microscopy (HRTEM), EDX를 이용하여 합성된 나노선의 결정학적 특성과 Mg의 도핑 농도를 확인하였다. Photo lithography와 e-beam lithography법을 이용하여 (Ga,Mg)N 나노선 field-effect transistor (FET)를 제작하고, channel current-drain voltage ($I_{ds}-V_{ds}$) 와 channel current-gate voltage ($I_{ds}-V_g$) 측정을 통해 (Ga,Mg)N 나노선이 도핑 농도에 따라 n형에서 p형으로 전기적 특성이 변화함을 확인하였다.

• Korean Journal of Metals and Materials
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• v.48 no.3
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• pp.262-267
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• 2010

$LiNi_{1-x}Mg_xO_2$(x=0, 0.025, 0.05, 0.075, 0.1) samples were synthesized by the solid-state reaction method. The crystal structure was analyzed by X-ray powder diffraction and Rietveld refinement. $LiNi_{1-x}Mg_xO_2$samples give single phases of hexagonal layered structures with a space group of R-3m. The calculated cation-anion distances and angles from the Rietveld refinement were changed with Mg contents in $LiNi_{1-x}Mg_xO_2$. The thicknesses of $NiO_2$ slabs were increased and the distances between the $NiO_2$ slabs were decreased with the increase in Mg contents in the samples. The electrical conductivities of sintered $LiNi_{1-x}Mg_xO_2$ samples were around $10^{-2}$ S/cm at room temperature. The electrochemical performances of $LiNi_{1-x}Mg_xO_2$were evaluated by coin cell test. Compared to $LiNiO_2$, $LiNi_{0.95}Mg_{0.05}O_2$ exhibited improved high-rate capability and cyclability due to the well-ordered layered structure by doping of Mg ion.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.2
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• pp.106-112
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• 2010

In order to compete with other flat display devices such as Liquid Crystal Displays (LCDs) and organic light emitting diodes (OLEDs), Plasma Display Panels (PDPs) require to have high performances like high image quality, low power consumption and high speed driving. In this paper, Fe doped MgO protective layer was introduced for higher performance. Both the surface characteristics of the deposited thin films and the electro-optical properties of 4 inch test panels were investigated. It has been demonstrated experimentally that ac PDP with Fe doped MgO protective layer has lower discharge voltage than that of undoped MgO film, which corresponds to measured secondary electron emission coefficients. The crystallinity and surface roughness of thin films were determined by XRD patterns and AFM images. In addition, ac PDP with Fe doped MgO protective layer has improved address discharge time lag for high speed driving.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.6 no.3
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• pp.368-376
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• 1996

$LiNbO_{3}$ single crystals (undoped, 5 mol% MgO-doped and 5 mol% ZnO-doped) were grown by the floating zone method which has the characteristics of a compositional homogeneity and uniform distribution of the dopants. The optimum growth condition was established experimentally and the defect structures such as domain structure, dislocation structure, slip band, and microtwins were characterized using a microscopic method.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.7
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• pp.562-566
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• 2001

The effects of MnO$_2$ addition on the properties in Pb(Mg$_{1}$3/Nb$_{2}$3/)O$_3$ relaxor ferroelectrics were studied in the phase transition temperature range from -4$0^{\circ}C$ to 11$0^{\circ}C$. Specimens were made via solid state processing method. Dielectric properties, piezoelctric properties, electric-field-induced strain were examined to clarify the effect of MnO$_2$ addition in 0.9MN-0.1PT. As the amount of MnO$_2$ increases, the maximum dielectric constant and the dielectric loss decreases. Q$_{m}$ increased by increasing the doping contents of Mn. When 0.5wt% MnO$_2$ was doped, Q$_{m}$ increased from 95 to 480. The electric-filed-induced strain and polarization decreases as the amount of MnO$_2$ increases. From the experimental results, it was suggested that Mn behaves as an ferroelectric domain pinning element.ent.

• Journal of Magnetics
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• v.12 no.4
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• pp.144-148
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• 2007

We report on the observation of p-type conductivity and ferromagnetism in diluted magnetic semiconductor $(Zn_{0.97}Mg_{0.01}Mn_{0.02})O:P$ films grown on $SiO_2/Si$ substrates by pulsed laser deposition. The p-type conduction with hole concentration over $10^{18}cm^{-3}$ is obtained by codoping of Mg and P followed by rapid thermal annealing in an $O_2$ atmosphere. Structural and compositional analyses for the p-type $(Zn_{0.97}Mg_{0.01}Mn_{0.02})O:P$ films annealed at $800^{\circ}C$ indicates that highly c-axis oriented homogeneous films were grown without any detectable formation of secondary phases. The films were found to be transparent in the visible range. The magnetic measurements clearly revealed an enhancement of room temperature ferromagnetism by p-type doping.

• Bulletin of the Korean Chemical Society
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• v.13 no.2
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• pp.127-131
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• 1992

Changes in network structures of ${\alpha}-Nb_2O_5$ in the X MgO+(1-X) ${\alpha}-Nb_2O_5$ solid solutions occurring as the MgO doping level (X) was varied were investigated by means of infrared spectroscopy and X-ray analysis. X-ray diffraction revealed that all the synthesized specimens have the monoclinic structure. The FT-IR spectroscopy showed that the system investigated forms the solid solutions in which $Mg^{2+}$ ions occupy the octahedral sites in parent crystal lattice. Electrical conductivities were measured as a function of temperature from 600 to $1050{\circ}$ and $P_{O2}$ form $1{\times}10^{-5}$ to $2{\times}10^{-1}$ atm. The defect structure and conduction mechanism were deduced from the results. The $1}n$ value in ${\alpha}{\propto}{P_{O2}^{1}n}}$ is found to be -1/4 with single possible defect model. From the activation energy ($E{\alpha}$ = 1.67-1.73 eV) and the1/n value, electronic conduction mechanism is suggested with a doubly charged oxygen vacancy.

• Archives of Pharmacal Research
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• v.27 no.2
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• pp.265-272
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• 2004

The pharmacokinetics of CKD-732 (6-0-4-[dimethyl-aminoethoxy)cinnamoyl]-fumagillolㆍhemioxalate) was investigated in male SD rats and beagle dogs after bolus intravenous administration. The parent compound and metabolites obtained from in vitro and in vivo samples were determined by LC/MS. The main metabolite was isolated and identified as an N-oxide form of CKD-732 by NMR and LC/MS/MS. CKD-732 was metabolized into either M11 or others by rapid hydroxylation, demethylation, and hydrolysis. The blood level following the intravenous route declined in first-order kinetics with $T_{1}$2/$\beta$ values of 0.72-0.78 h for CKD-732 and 0.92-1.09 h for M11 in rats at a dose of 7.5-30 mg/kg. In dogs, $T_{1}$2/$\beta$ values of CKD-732 and M11 were 1.54 and 1.79 h, respectively. Moreover, AUC values increased dose dependently for CKD-732 and M11 in rats and dogs. The CLtot and Vdss did not change significantly with increasing dose, indicating linear pharmacokinetic patterns. The excretion patterns through the urine, bile, and feces were also examined in the animals. The total amount excreted in urine, bile, and feces was 2.13% for CKD-732 and 1.29% for M11 in rats, and 1.58% for CKD-732 and 2.28% for M11 in dogs.

• Journal of the Korean institute of surface engineering
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• v.49 no.1
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• pp.40-45
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• 2016

Recently, $Bi_2Te_3$-based alloys are the best thermoelectric materials near to room temperature, so it has been researched to achieve increased figure of merit(ZT). Ternary compounds such as Bi-Te-Se and Bi-Sb-Te have higher thermoelectric property than binary compound Bi-Te and Sb-Te, respectively. Compared to DC plating method, pulsed electrodeposition is able to control parameters including average current density, and on/off pulse time etc. Thereby the morphology and properties of the films can be improved. In this study, we electrodeposited n-type ternary Cu-doped $Bi_2(Te-Se)_3$ thin film by modified pulse technique at room temperature. To further enhance thermoelectric properties of $Bi_2(Te-Se)_3$ thin film, we optimized Cu doping concentration in $Bi_2(Te-Se)_3$ thin film and correlated it to electrical and thermoelectric properties. Thus, the crystal, electrical, and thermoelectric properties of electrodeposited $Bi_2(Te-Se)_3$ thin film were characterized the XRD, SEM, EDS, Seebeck measurement, and Hall effect measurement, respectively. As a result, the thermoelectric properties of Cu-doped $Bi_2(Te-Se)_3$ thin films were observed that the Seebeck coefficient is $-101.2{\mu}V/K$ and the power factor is $1412.6{\mu}W/mK^2$ at 10 mg of Cu weight. The power factor of Cu-doped $Bi_2(Te-Se)_3$ thin film is 1.4 times higher than undoped $Bi_2(Te-Se)_3$ thin film.

• JSTS:Journal of Semiconductor Technology and Science
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• v.16 no.2
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• pp.198-203
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• 2016

We investigate the effects of magnesium (Mg) suppressor layer on the electrical performances and stabilities of amorphous indium-zinc-tin-oxide (a-ITZO) thin-film transistors (TFTs). Compared to the ITZO TFT without a Mg suppressor layer, the ITZO:Mg TFT exhibits slightly smaller field-effect mobility and much reduced subthreshold slope. The ITZO:Mg TFT shows improved electrical stabilities compared to the ITZO TFT under both positive-bias and negative-bias-illumination stresses. From the X-ray photoelectron spectroscopy O1s spectra with fitted curves for ITZO and ITZO:Mg films, we observe that Mg doping contributes to an enhancement of the oxygen bond without oxygen vacancy and a reduction of the oxygen bonds with oxygen vacancies. This result shows that the Mg can be an effective suppressor in a-ITZO TFTs.