• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.5
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• pp.347-350
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• 2013

By inserting a very thin metal layer of Ag between two outer oxide layers of amorphous silicon indium zinc oxide (SIZO), we fabricated a highly transparent SIZO/Ag/SIZO multilayer on a glass substrate. In order to find the optimized thickness of Ag layers, we investigated the variation of optical properties depending on Ag thickness. It was found that the transition of Ag layer from island formation to a continuous film occurred at a critical thickness. Continuity of the Ag film is very important for optical properties in SIZO/Ag/SIZO multilayer. With about 15 nm thick Ag layer, the multilayer showed a high optical transmittance of 80% at 550 nm and low emissivity in IR.

• Journal of the Korean Ceramic Society
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• v.37 no.8
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• pp.774-780
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• 2000

In order to improve luminescence prperty of phosphors, we have synthesized Zn2SiO4:Mn phosphors by a new chemical synthetic route, i.e., the homogeneous precipitation method. This method has featured that the formation of phosphoris completed at relatively low temperature of 105$0^{\circ}C$ and the particle morphology exhibits spherical shape to be well-dispersed and uniform size. At all the Mn concentration explored, phosphors prepared by this method have exhibited the improved emission intensities. In particular, the emission intensities of phosphors with Mn doping contents between 1 at% and 3.5 at% were higher about 40% than that of commercial phosphor. On the other hand, the decay time has been decreased from 23 ms to 11 ms with increasing Mn concentration. In addition, the phosphor composition containing 3 at% Mn has displayed the most saturated color.

• Korean Journal of Materials Research
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• v.5 no.8
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• pp.1026-1034
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• 1995

It is well known that the addition of CaO-SiO$_2$to Mn-Zn ferrites forms an insulating grain bounary layer with high electrical resistivity. This study investigated the effect of Nb$_2$O$_{5}$ on the electromagnetic properties of high frequency low loss Mn-Zn ferrites. The addition of 300ppm Nb$_2$O$_{5}$ developed an exaggerated grain growth while the addition of CaO-SiO$_2$addition with 200ppm Nb$_2$O$_{5}$ more effectively increased the density than that without Nb$_2$O$_{5}$. The addition of Nb$_2$O$_{5}$ showed the lower power loss below 100 ppm SiO$_2$and the Nb$_2$O$_{5}$-CaO addition lowered the power loss at higher sintering temperature.

• Journal of Sensor Science and Technology
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• v.5 no.1
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• pp.37-42
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• 1996

ZnO films have been deposited on oxide grown Si wafers by the conventional thermal evaporation method. Anhydrous zinc acetate was directly heated and sublimed in the laboratory-made brass boat. The substrates temperature varied from $200^{\circ}C$ to $600^{\circ}C$. Oxygen has been flowed into the deposition chamber to change the partial pressure of oxygen. The films deposited at high oxygen pressure exhibited higher resistivity than films at low pressure. X-Ray Diffraction(XRD), Energy Dispersive Spectroscopy(EDS) and Rutherford Backscattering Spectrometry (RBS) were conducted on the films to reveal the crystallinity and composition of the ZnO films. The ZnO films deposited at high oxygen pressure were extremly sensitive to the humidity of higher than 70 % RH.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.236.1-236.1
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• 2015

The surface morphology of front transparent conductive oxide (TCO) films is very important to achieve high current density in amorphous silicon (a-Si) thin film solar cells since it can scatter the light in a better way. In this study, we present the low cost hydrothermal deposited uniform zinc oxide (ZnO) nano-flower structure with various aspect ratios for a-Si thin film solar cells. The ZnO nano-flower structures with various aspect ratios were grown on the RF magnetron sputtered AZO films. The diameters and length of the ZnO nano-flowers was controlled by varying the annealing time. The length of ZnO nano-flowers were varied from 400 nm to $2{\mu}m$ while diameter was kept higher than 200 nm to obtain different aspect ratios. The ZnO nano-flowers with higher surface area as compared to conventional ZnO nano structure are preferred for the better light scattering. The conductivity and crystallinity of ZnO nano-flowers can be enhanced by annealing in hydrogen atmosphere at 350 oC. The vertical aligned ZnO nano-flowers showed higher haze ratio as compared to the commercially available FTO films. We also observed that the scattering in the longer wavelength region was favored for the high aspect ratio of ZnO nano-flowers. Therefore, we proposed low cost and vertically aligned ZnO nano-flowers for the high performance of thin film solar cells.

• Journal of Sensor Science and Technology
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• v.8 no.3
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• pp.274-282
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• 1999

The In doped ZnO(ZnO:In)thin films sensitive to $NH_3$ gas were prepared by the double layer depositions of In film by vacuum evaporation and ZnO film by rf magnetron sputtering method onto a $SiO_2$/Si wafer substrate, and subsequent heat treatment process. The structural and electrical characteristics of the ZnO:In thin films were studied as a function of heat treatment temperature by x-ray diffraction, scanning electron microscope and 4 point probing method. And the dependence of the sensitivity, the selectivity and the time response of the thin films on heat treatment temperature was investigated. The thin film heat-treated at $400^{\circ}C$ showed the highest sensitivity of 140% at an operating temperature of $300^{\circ}C$. The sensitivity towards CO, $NO_x$, gases observed in the same temperature.

• Proceedings of the Korea Contents Association Conference
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• 2007.11a
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• pp.804-806
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• 2007

C-axis oriented zinc oxide thin films were deposited on Si(100) substrate by rf magnetron sputtering. The effects of deposition parameters on the crystallinity and electrical properties of ZnO films were investigated. As-deposited ZnO films showed the strong c-axis growth andexcellent crystallinity under the deposition conditions as follows ; substrate temperaturec : $200^{\circ}C$, rf power : 150W, gas ratio : $O_2/Ar=50/50$, chamber pressure : 10mTorr. The resistivity of ZnO films was significantly affected by deposition parameters. With increasing percentage of oxygen, and decreasing substrate temperature, the resistivity of ZnO films increased.

• Journal of the Semiconductor & Display Technology
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• v.21 no.4
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• pp.106-109
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• 2022

The green-emitting Zn₂SiO₄:Mn²⁺ phosphor film was evaluated in a xenon excimer lamp. The phosphor film with 2 ㎛ thick was formed of monolithic structure on the inner side of quartz through a long-time annealing process of coated ZnO solution doped with Mn²⁺ ion and SiO₂ of quartz tube. The coated quartz was filled with 100 torr of xenon gas, and simultaneously both sides was melt and sealed. The xenon-field quartz tube was discharge by applying the voltage of 15 kV with a frequency of 26 kHz, and emitted the glow with dominant peak at 172 nm. The vacuum ultraviolet excited the inner-side coated Zn₂SiO₄:Mn²⁺ phosphor film, which emitted the pure and strong green light.

• Korean Journal of Optics and Photonics
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• v.3 no.4
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• pp.205-216
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• 1992

Distribution of electric fields of surface plasmons at resonance and off-resonance angles were calculated and compared. As applications of surface plasmon resonance, (1) optical constants of ZnS films overcoated on Ag films were measured as the thickness of ZnS films increased, (2) four surface plasmon resonances distributed spatially due to the different thickness of SiO thin films overcoated on Ag films were observed in a picture frame by employing diverging waves of incidence, and (3) patterns of SiO thin films such as a grating and a character "가" overcoated on Ag films were measured by employing collimated waves of incidence.

• Proceedings of the KIEE Conference
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• 1987.07a
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• pp.556-560
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• 1987

To enhance the breakdown properties of low voltage-oriented ZnO varistor, the samples were fabricated with the amounts of si-oxides and the sintering conditions. And then, to lower the breakdown voltage the $TiO_2$-added samples were fabricated. We investigated the nonlinear exponent, the nonlinear resistance and the V-I characteristics of samples. And we discussed with microstructures by use of SEM and the position of Si by EDS. Si-oxides, especially, largely enhanced the nonlinear exponent. In this case optimum sintering condition was $1200-1250^{\circ}C$-1hr and $TiO_2$ addition lowered the breakdown voltage.