• Korean Journal of Metals and Materials
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• v.46 no.4
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• pp.249-256
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• 2008

0.5 wt% Al doped ZnO thin films (AZO) were prepared on glass substrates using RF magnetron sputtering method. Thin films were grown at substrate temperature of $250^{\circ}C$, RF power of 75W, working pressure of 10 mTorr, by changing the $O_2/Ar$ pressure ratio from 0% to 16.7%. The effects of oxygen partial pressure during the deposition process on structural and optical properties of the films were investigated using XRD, SEM, AFM, EPMA and UV-visible spectroscopy. All the AZO thin films were grown as hexagonal wurtzite phase with the c-axis preferred out-of-plane orientation. The surface roughness and grain size of AZO films decreased with increasing oxygen ratio from 10.6 nm to 3.2 nm and 94.9 nm to 30.9 nm, respectively. On the other hand, the transmittance and band gap energy of the AZO films increased from 84.7% to 92.6% and 3.24 eV to 3.28 eV, respectively with increasing the $O_2/Ar$ pressure ratio.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.1
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• pp.47-52
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• 2024

The effects of annealing temperature on the optical and electrical properties of BZO thin films, grown on glass substrate, have been investigated. Analysis of the XRD shows that regardless of the annealing temperature, all BZO thin films indicate the c-axis orientation. The full width of half maximum (FWHM) decreases from 1.65 to 1.07° as the annealing temperature increases from 400 to 600℃. The average transmittance in the visible light region showed a high value of 85% without significantly affecting the annealing temperature. The results of Hall effect measurements indicate that the carrier concentration and mobility increased and the resistivity decreased as the annealing temperature increased. The resistivity and the carrier concentration of the BZO thin films annealed 600℃ were 9.75×10^-2 Ω·cm and 4.21×10¹⁹ cm^-3 respectively, showing the best value. The optimization of deposition and annealing conditions will certainly make the BZO thin films promising materials for the application to the next generation of optoelectronic devices.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.2 s.344
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• pp.8-12
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• 2006

We have fabricated ZnO thin film on $Pt/TiO-2/SiO_2/Si$ substrate by the sol-gel method and have investigated the effect of annealing temperature on the structural morphology and optical properties of ZnO thin films. The ZnO thin film annealed at $600^{\circ}C$ exhibits the highest c-axis orientation and its FWHM of X-ray peak is $0.4360^{\circ}C$. In the results of surface morphology investigation of ZnO thin film by using Am it is observed that ZnO thin film annealed at $600^{\circ}C$ exhibits the largest UV (ultraviolet) exciton emission at around 378nm and the smallest visible emission at around 510nm among these of ZnO thin films annealed at various temperatures. It is deduced that the ZnO thim film annealed at $600^{\circ}C$ is formed most stoichiometrically since the visible emission at around 510nm comes from oxygen vacancy or impurities.

• Journal of the Korean Ceramic Society
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• v.41 no.2
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• pp.170-175
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• 2004

The ferroelectric (Y $b_{x}$ $Y_{1-x}$)Mn $O_3$ thin films were fabricated by sol-gel method using Y-acetate, Yb-acetate, and Mn-acetate as raw materials. The stable (Y $b_{x}$ $Y_{1-x}$)Mn $O_3$ precursor solution (sol) was prepared through the reflux process with acetylaceton as a catalyst and coated on Si(100) substrate by spin coating. The heat treatment temperature and, Rw ($H_2O$/alkoxide moi ratio) dependence on crystallinity of thin films were studied. The lowest temperature for obtaining YbMn $O_3$phase and the optimum heat-treatment conditions were proved as at 7$50^{\circ}C$ and 80$0^{\circ}C$, respectively. The hexagonal YbMn $O_3$with c-axis preferred orientation could be obtained at Rw=1 condition. The remanent polarization for the thin films of x=0 or 1 was about 200 nC/㎤ while, for the specimens ot 0< x< 1, were 50∼100 nC/$\textrm{cm}^2$.

• Journal of the Korean Vacuum Society
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• v.20 no.1
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• pp.50-56
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• 2011

In this study, the effects of ZnO buffer layer thickness and annealing temperature on the heterojunction diode, ZnO/b-ZnO/p-Si(111), were reported. The effects of those on the structural and electrical properties of zinc oxide (ZnO) films on ZnO buffered p-Si (111) substrate were also studied. Structural properties of ZnO thin films were studied by X-ray diffraction and I-V characteristics were measured by a semiconductor parameter analyzer. ZnO thin films with 70 nm thick buffer layer and annealing temperature of $700^{\circ}C$ showed the best c-axis preferred orientation. The best electrical property was found at the condition of buffer layer annealing temperature of $700^{\circ}C$ and 50nm thick ZnO buffer layer (resistivity: $2.58{\times}10^{-4}[{\Omega}-cm]$, carrier concentration: $1.16{\times}1020[cm^{-3}]$). The I-V characteristics for ZnO/b-ZnO/p-Si(111) heterojunction diode were improved with increasing buffer layer thickness at buffer layer annealing temperature of $700^{\circ}C$.

• Progress in Superconductivity
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• v.8 no.1
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• pp.65-70
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• 2006

We fabricated $YBa_2Cu_33O_{7-x}$(YBCO) films on(00l) $LaAlO_3$ substrates prepared by metal organic deposition(MOD) method using trifluoroacetate(TFA) solution and evaluated the effects of the humidity on the microstructure, phase purity, and critical properties. The films calcined at $430^{\circ}C$ were fired at $775^{\circ}C$ at 0%, 4.2%, 12.1%, and 20.0% humidified As gas mixed with 0.1% $O_2$. We observed that the amount of $BaF_2$ phase was effectively reduced and that a sharp and strong biaxial texture formed under a humidified atmosphere, leading to increased critical properties. For the films fired at 0% humidity, the $T_c\;and\;I_c$ were undetectably small. When the humidity was increased to 4.2%, the corresponding $T_c$(onset) and $I_c$ were increased to 90.5 K and 8 A/cm-width, respectively. For the films at the humidity range of 12.1-20.0%, the $I_c$ was found to be 35 A/cm-width. According to the results of the XRD, pole-figure, and SEM, these improved critical properties are probably attributed to the formation of a purer YBCO phase, larger grain size, and stronger c-axis orientation.

• Journal of the Korean Magnetics Society
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• v.8 no.3
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• pp.156-160
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• 1998

Crystal structures and magneto-optical properties of $(Mn_{0.5-Z}Sb_{0.5+Z})_{100-y}Pt_y$ (0$(Mn_{0.5-Z}Sb_{0.5+Z})_{100-y}Ag_y$ (0$^{\circ}C$ are C1b-type with fcc and NiAs-type with hcp, respectively. The MnSbAg films have a texture which the c-axis orientation is perpendicular to the film plane by annealing at 300 $^{\circ}C$ for less than 3 hours. The perpendicular anisotropy constants of the $Mn_{47.4}Sb_{47.5}Ag_{5.1}$ film annealed at 300 $^{\circ}C$ for 3 hours are $K_1=6.6{\times}10^5 \; erg/cm^3\;and\;K_2=1.9{\times}10^5\; erg/cm^3$. The Kerr rotation angle of MnSbPt films increases but that of MnSbAg film decreases by decreasing incident wavelength within the range of 700$\leq$ λ$\leq$1000 nm. High polar Kerr angles of 1.7$^{\circ}$ (λ =700 nm) and 0.6$^{\circ}$ (λ =1000 nm), 0.2$^{\circ}$ (λ =700 nm) and 0.97$^{\circ}$ (λ =1000 nm) have been obtained from $Mn_{41.1}Sb_{44,9}Pt_{14.0}$ and $Mn_{47.4}Sb_{47.5}Ag_{5.1}$ alloy films, respectively.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.5
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• pp.1213-1218
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• 2013

In this study, Ga-doped ZnO (GZO) thin films were fabricated on transparent sapphire substrate by RF magnetron sputtering method and then investigated the effect of various substrate temperature on the electrical, optical properties and characteristic of crystallization of the GZO thin films. The electrical property indicated that the lowest resistivity ($4.18{\times}10^{-4}{\Omega}cm$), the highest carrier concentration ($6.77{\times}10^{20}cm^{-3}$) and Hall mobility ($22cm^2/Vs$) were obtained in the GZO thin film fabricated at $300^{\circ}C$. And for this condition, the highest c-axis orientation and (002) diffraction peak which exhibits a FWHM of $0.34^{\circ}$ were obtained. From the results of AFM measurements, it is known that the highest crystallinity is observed at $300^{\circ}C$. The transmittance spectrum in the visible range was approximately 80 % regardless of substrate temperature. The optical band-gap showed the blue-shift as increasing the substrate temperature to $300^{\circ}C$, and they are all larger than the band gap of bulk ZnO (3.3 eV). It can be explained by the Burstein-Moss effect.

• Geomechanics and Engineering
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• v.23 no.3
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• pp.245-259
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• 2020

Tunnels have become an indispensable part of metro cities. Blast resistance design of tunnel has attracted the attention of researchers due to numerous implosion event. Present paper deals with the non-linear finite element analysis of rock tunnel having shear zone subjected to internal blast loading. Abaqus Explicit schemes in finite element has been used for the simulation of internal blast event. Structural discontinuity i.e., shear zone has been assumed passing the tunnel cross-section in the vertical direction and consist of Highly Weathered Granite medium surrounding the tunnel. Mohr-Coulomb constitutive material model has been considered for modelling the Highly Weathered Granite and the shear zone material. Concrete Damage Plasticity (CDP), Johnson-Cook (J-C), Jones-Wilkins-Lee (JWL) equation of state models are used for concrete, steel reinforcement and Trinitrotoluene (TNT) simulation respectively. The Coupled-Eulerian-Lagrangian (CEL) method of modelling for TNT explosive and air inside the tunnel has been adopted in this study. The CEL method incorporates the large deformations for which the traditional finite element analysis cannot be used. Shear zone orientations of 0°, 15°, 30°, 45°, 60°, 75° and 90°, with respect to the tunnel axis are considered to see their effect. It has been concluded that 60° orientation of shear zone presents the most critical situation.

• Journal of the Korean Ceramic Society
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• v.53 no.4
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• pp.417-428
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• 2016

In this review, an attempt is made to calculate one-dimensional (1-D) electron density profiles from experimentally determined (00l) XRD intensities and possible structural models as well in an effort to understand the collective intracrystalline structures of intercalant molecules of two-dimensional (2-D) nanohybrids with heterostructures. 2-D ceramics, including layered metal oxides and clays, have received much attention due to their potential applicability as catalysts, electrodes, stabilizing agents, and drug delivery systems. 2-D nanohybrids based on such layered ceramics with various heterostructures have been realized through intercalation reactions. In general, the physico-chemical properties of such 2-D nanohybrids are strongly correlated with their heterostructures, but it is not easy to solve the crystal structures due to their low crystallinity and high anisotropic nature. However, the powder X-ray diffraction (XRD) analysis method is thought to be the most powerful means of understanding the interlayer structures of intercalant molecules. If a proper number of well-developed (00l) XRD peaks are available for such 2-D nanohybrids, the 1-D electron density along the crystallographic c-axis can be calculated via a Fourier transform analysis to obtain structural information about the orientations and arrangements of guest species in the interlayer space.