• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.113-114
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• 2005

We present the effect of substrate temperature on the structural and optical properties of ZnO films grown on sapphire substrate by pulsed laser deposition. Growing at higher substrate temperature results in an increase in the surface roughness. The optimum c-axis orientation of the ZnO films occurs at the substrate temperature of 700$^{\circ}C$ The decay time shows a rapid increase in the substrate temperature from 400$^{\circ}C$ to 500$^{\circ}C$ and falls down gradually as the substrate temperature is approached to 700$^{\circ}C$.

• Journal of the Korean Vacuum Society
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• v.16 no.6
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• pp.463-467
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• 2007

Structure and optical properties of ZnO epilayers grown on oxygen- and hydrogen-plasma treated sapphire substrates by plasma-assisted molecular beam epitaxy (denoted as samples A and B, respectively) have been investigated by various techniques. The crystal quality and structural properties of the surface for the ZnO epilayers were investigated by high-resolution X-ray diffraction and atomic force microscope. For investigating the optical properties of excitonic transition of ZnO, we carried out photoluminescence experiments as a function of temperature. The free exciton, bound exciton emission and their phonon replicas were investigated as a function of temperature from 10 to 300 K, and the intensity of excitonic PL peak emission from the sample A is found to be higher than that of sample B. From the results, we found that sample A has better crystal structure quality and optical properties as compared to sample B. The number of oxygen vacancies may be decreased in sample A, resulting in an enhancement of the crystal quality and a higher intensity of excitonic emission band as compared to sample B.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.11
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• pp.36-43
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• 2008

In this parer aluminium-doped zinc oxide(ZnO:Al) conducting layer was deposited on polyethylene terephthalate(PET) substrate by r. f. magnetron sputtering method. The effects of gas pressure and r. f. sputtering power on the structural and electrical properties of ZnO:Al thin film were investigated experimentally. Especially the effect of position of PET substrate on the electrical properties of the film was studied and fixed to improve the electrical properties and also to increase the deposition rate. The results show that the structural and electrical properties of ZnO:Al thin film were strongly influenced by the gas pressure and sputtering power. The minimum resistivity of $1.1{\times}10^{-3}[{\Omega}-cm]$ was obtained at 5[mTorr] of gas pressure, and 18D[W] of sputtering power. The deposition rate of ZnO:Al film at 5[mTorr] of gas pressure was 248[nm/min]. and is higher by around 3 times compared to that at 25[mTorr].

• Journal of the Semiconductor & Display Technology
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• v.15 no.3
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• pp.57-61
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• 2016

We have studied the structural, optical and electrical properties of IGZO thin films. The IGZO thin films were deposited on the silicon wafer by RF magnetron sputtering method. The RF power in sputtering process was varied as 15W, 30W, 45W, 60W, 75W, respectively. All of the thin films transmittance in the visible range was above 85%. XRD analysis showed that amorphous structure of the thin films without any peak. The Hall measurements in the low RF power is the high mobility above $10cm^2/V{\cdot}s$ and the low resistvity are obtained in the IGZO thin films.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.1859-1861
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• 2005

The ZnO:Al thin films were prepared on glass by Facing Target Sputtering (FTS) system. We investigated electrical, optical, and structural properties of AZO thin film with sputtering current $0.1[A]{\sim}0.6[A]$. We obtained the lowest resistivity $2.3{\times}10^{-4}[{\Omega}-cm]$ at sputtering current 0.6[A] from the 4-point probe and the strong (002) peak at sputtering current 0.3[A] from the X-ray Diffractometer (XRD ). The optical transmittance of AZO thin films show a very high transmittance of $80{\sim}95%$ in the visible range and exhibit the absorption edge of about 350nm.

• Current Optics and Photonics
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• v.3 no.4
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• pp.304-310
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• 2019

In this paper, a microstructured, hexagonal-shaped dual-core photonic crystal fiber (PCF) is proposed. The proposed structure has specific optical properties to obtain high birefringence and short coupling length, for different values of structural parameters varied over a wide range of wavelength. The properties are analyzed using a solid core of silica material. The proposed structure is implemented as a polarization splitter with splitting length of 1.9 mm and a splitting ratio of -34.988 dB, at a wavelength of 1550 nm. The obtained bandwidth in one band gap of about 81 nm. The numerical analysis ensures that the performance of the proposed polarization splitter is better than that of existing ones.

• Journal of the Korean Vacuum Society
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• v.17 no.1
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• pp.51-57
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• 2008

we have demonstrated structural evolution and optical properties of Si-nanowires (NWs) synthesized on Si (111) substrates with nanoscale Au-Si islands by rapid thermal chemical vapor deposition (RTCVD). The Au-Si nano-islands (10-50nm in diameter) were employed as a liquid-droplet catalysis to grow Si-NWs via vapor-liquid-solid mechanism. The Si-NWs were grown by a mixture gas of SiH4 and H2 at a pressure of 1.0 Torr and temperatures of $500{\sim}600^{\circ}C$. Scanning electron microscopy measurements showed that the Si-NWs are uniformly sized and vertically well-aligned along <111> direction on Si (111) surfaces. The resulting NWs are ${\sim}60nm$ in average diameter and ${\sim}5um$ in average length. High resolution transmission microscopy measurements indicated that the NWs are single crystals covered with amorphous SiOx layers of ${\sim}3nm$ thickness. In addition, the optical properties of the NWs were investigated by micro-Raman spectroscopy. The downshift and asymmetric broadening of the Si main optical phonon peak were observed in Raman spectra of Si-NWs, which indicates a minute stress effects on Raman spectra due to a slight lattice distortion led by lattice expansion of Si-NW structures.

• Korean Journal of Metals and Materials
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• v.50 no.8
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• pp.605-611
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• 2012

ZnO nanostructures were grown on R-plane sapphire substrates with seed layers annealed at different temperatures ranging from 600 to $800^{\circ}C$. The properties of the ZnO nanostructures were investigated by scanning electron microscopy, high-resolution X-ray diffraction, UV-visible spectrophotometer, and photoluminescence. For the as-prepared seed layers, ZnO nanorods and ZnO nanosheets were observed. However, only ZnO nanorods were grown when the annealing temperature was above $700^{\circ}C$. The crystal qualities of the ZnO nanostructures were enhanced when the seed layers were annealed at $700^{\circ}C$. In addition, the full width at half maximum (FWHM) of near-band-edge emission (NBE) peak was decreased from 139 to 129 meV by increasing the annealing temperature to $700^{\circ}C$. However, the FWHM was slightly increased again by a further increase in the annealing temperature. Optical transmittance in the UV region was almost zero, while that in the visible region was gradually increased as the annealing temperature increased to $700^{\circ}C$. The optical band gap of the ZnO nanostructures was increased as the annealing temperature increased to $700^{\circ}C$. It is found that the optical properties as well as the structural properties of the rod-shaped ZnO nanostructures grown on R-plane sapphire substrates by hydrothermal method are improved when the seed layers are annealed at $700^{\circ}C$.

• Textile Coloration and Finishing
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• v.33 no.3
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• pp.131-140
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• 2021

Collagen and chitosan are used in medical and cosmetic materials as natural polymers. In order to utilize the advantages of the materials, collagen/chitosan conjugated wet-spun fibers were prepared. The analysis of surface, optical, thermal and mechanical properties was carried out on the various composition of collagen and chitosan. As a result of images analysis, it was verified that the collagen/chitosan conjugated fibers were stably spun. In addition, the optical and thermal properties of fibers were observed to be changed by hydrogen bond. As a result, an optimized composition could be found at an appropriate content. Moreover, the optimized fibers have mechanical properties similar to chitosan fibers, while improving the structural and thermal stability by its hydrogen bond. In addition, the wet-spun collagen/chitosan conjugated fibers can be applied to medical and various fields through mechanical properties according to content control.

• Proceedings of the Korean Vacuum Society Conference
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• 2009.08a
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• pp.177-177
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• 2009