• Journal of the Korean Society of Radiology
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• v.14 no.5
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• pp.695-703
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• 2020

The use of medical devices is increasing due to the development of medical technology. Among medical devices, it is often used in the human body for graft and treatment. Therefore, in medical institutions, various sterilization methods according to the type and material of medical devices are applied to prevent infection. Hydrophosphite (HA) materials are the most popular in bone grafts. We would like to present a sterilization method using Q-switch Nd:YAG laser with high output energy among non-ionizing radiation suitable for small medical devices. In this study, sterilization power was most ideally shown at UV wavelengths of 1.5 W, 266 nm, and 10 pulses. Different wavelength bands; infrared and visible light; showed passive sterilization, and ultraviolet A and C showed differences in sterilization according to the pulse. In laser sterilization were differences that found according to the wavelength bands and pulses.

• Journal of the Korean Ceramic Society
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• v.39 no.12
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• pp.1158-1163
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• 2002

An Ge/B-doped optical fiber with high photosensitivity was fabricated to induce large second-order optical nonlinearity by UV poling. It was found that long period fiber gratings were inscribed on the fiber by the 248 nm KrF excimer laser irradiation with pulse energy of 116 mJ/$cm^2$ and pulse frequency of 10 Hz without hydrogen loading treatment. The photosensitivity was measured by use of the long period fiber grating pair method and the refractive index change of 3.3$10{\times}^{-3}$ was found to be induced in the core of the optical fiber by the KrF excimer laser irradiation of 8.67 kJ/$cm^2$. An H-shaped optical fiber was also fabricated for the UV poling through optimization of the fiber drawing condition.

• Journal of the Korean Vacuum Society
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• v.6 no.2
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• pp.114-121
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• 1997

The transparent conductiong thin films of tin oxides were prepared on pyrex glass substrates by the pulse laser deposition. In the atmospheres of vacuum, O2, and $Sn(CH_3)_4$ a polycrystalline $SnO_2$ target was ablated by Nd-YAG laser beam to deposit thin films on the substrates at room temperature, and as-deposited films were subsequently heat-treated in the air for 2 h at 230, 420 and $610^{\circ}C$, respectively. The characteristics of the thin films were examined by UV-VIS-NIR spectrometry and X-ray diffractometry, and the electrical properties were measured by four-point probe method along with film thickness monitored by the stylus method. It was observed that in the presence of $Sn(CH_3)_4$, $SnO_2$ phases were grown even at room temperature. This suggests that the microplasma producted during the laser ablation plays an important role in the dissociaation of precursor molecules.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.5
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• pp.2979-2984
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• 2015

This paper has presented a new foaming technology of selective hybrid-structured polymer film with expanded pores. The porous structure of closed pore was firstly fabricated by applying the 355nm UV-pulsed laser to 0.1mm thick film that was uniformly mixed with PP pellets, copper powder, and CBA (Chemical Blowing Agent). In order to expand pore size of closed-cell shape, LAMO(Laser Aided Micro pore Opening) processing was conducted to heat the copper powder, and then the bigger pore size of closed-cell more than existing pore size was successfully formed because of rapid conduction of heated metal powder. From the experimental results, various process parameters such as laser fluence, intensity, scan rate, spot size and density of powder and CBA were considerably considered to reveal the correlation among the pore characteristics. In the future, a function experiment will be carried out to use the hybrid film of industrial applications.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.04a
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• pp.125-128
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• 2000

ZnO thin films on silicon substrates have been deposited by pulsed laser deposition technique(PLD). A Nd:YAG laser was used with the wavelength of 355 nm. In order to investigate the effect of oxygen post-annealing treatment on the property of ZnO thin films, deposited film has been annealed at the substrate temperature of $440^{\circ}C$. After post-annealing treatment in the oxygen ambient, the stoichiometry of ZnO film has been characterized be improved which results in higher UV emission intensity of photoluminescence.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.166-166
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• 2007

PRAM (phase-change random access memory)은 전류 펄스 인가에 따른 기록매질의 비정질-결정질 간 상변화와 그에 동반되는 저항변화를 이용하는 차세대 비휘발성 메모리 소자로서 연구되어지고 있다. 본 논문에서는 $(Ge_2Sb_2Te_5)_{1-x}Se_x$ (x=0,0.05,0.1,0.15) 조성에 대한 벌크 및 박막시료를 제작하고 각 조성에 대한 상변화 특성을 분석하였다. XRD를 통해 열처리 온도에 따른 구조적 분석을 실시하였고 UV-Vis-IR spectrophotometer를 사용하여 박막의 광학적 특성을 분석하였다. 또한 각 조성의 결정화 속도를 비교하기 위해 static tester를 사용하여 레이저 펄스 시간에 대한 반사도 변화를 측정하였고 DSC를 통해 결정화 온도를 측정하였다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.3
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• pp.329-332
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• 2004

ZnO thin films were grown with different plume-substrate angles by pulsed laser deposition (PLD) to control the amount of ablated species arriving on a substrate per laser shot. The angles between plume propagation direction and substrate plane (P-S angle) were 0$^{\circ}$, 45$^{\circ}$ and 90$^{\circ}$. The growth time was changed in order to adjust film thickness. From the XRD pattern exhibiting a dominant (002) and a minor (101) XRD peak of ZnO, all films were found to be well oriented along c-axis. From the AFM image, it was found that the grain size of ZnO thin film was increased, as P-S angle decreased. UV intensity investigated by PL (Photoluminescence) increased as P-S angle decreased.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.1
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• pp.65-69
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• 2003

ZnO-Si-ZnO multi-layer thin films have been deposited by pulsed laser deposition (PLD). And then, the films have been annealed at 300$^{\circ}C$ in oxygen ambient pressure. Peak positions of ultraviolet (UV) and visible region were changed by addition of Si layer. Mobility of the films was improved slightly than ZnO thin film without Si layer. The structural property changed by inserting intermediate Si layer in ZnO thin film. The optical properties and structural properties of ZnO-Si-ZnO multi-layer thin films were characterized by PL(Photoluminescence) and XRB(X-ray diffraction) method, respectively. Electrical properties were measured by van der Pauw Hall measurements

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.539-542
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• 2000

ZnO thin films for light emission device have been deposited on sapphire and silicon substrates by pulsed laser deposition technique(PLD). A Nd:YAG laser was used with the wavelength of 355 nm. In order to investigate the emission properties of ZnO thin films, PL measurements with an Ar ion laser as a light source using an excitation wavelength of 351 nm and a power of 100 mW are used. All spectra were taken at room temperature by using a grating spectrometer and a photomultiplier detector. ZnO exhibited PL bands centered around 390, 510 and 640 nm, labeled near ultra-violet (UV), green and orange bands. Structural properties of ZnO thin films are analized with X-ray diffraction (XRD).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.200-202
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• 2004

ZnO thin films were grown at different plume-substrate angles by pulsed laser deposition(PLD). From the X-ray diffraction(XRD) result, all ZnO thin films were found to be well c-axis oriented and c-axis lattice constant approached the value of bulk ZnO as plume-substrate(P-S) angle decreased. The grain size of ZnO thin films measured by atomic force microscopy increased and the UV intensity of ZnO thin films investigated by photoluminescence increased as P-S angle decreased. It is found that the improvement of structural and optical properties mainly comes from the reduction of the flux of ablated species arriving on a substrate per a laser shot by tilting a substrate parallel to the plume propagation direction.