• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 Techno-Fair 및 추계학술대회 논문집 전기물성,응용부문
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• pp.88-89
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• 2007

ZnO thin films were deposited on $Al_2O_3$ (alumina) substrates by pulsed laser deposition (PLD) using Nd:YAG laser with a wavelength of 355nm, at room temperature and oxygen partial pressure of 1, 10, 30, 50, 100, and 200m Torr. Furthermore, deposited ZnO thin films were post-annealed at 400, 550, $600^{\circ}C$. The effects of oxygen partial pressure and post-annealing temperature on structural properties of the deposited films have been investigated by means of X-ray diffraction (XRD), and atomic force microscope (AFM), respectively. It has been found that ZnO thin films exhibit c-axis orientation, exhibiting an increased foil width at half maximum (FWHM) value of (002) diffraction peak at 30m Torr oxygen partial pressure and higher post-annealing temperature ($700^{\circ}C$).

• 한국진공학회:학술대회논문집
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• 한국진공학회 2004년도 제26회 학술발표회 초록집
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• pp.169-169
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• 2004

• 세라미스트
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• 제10권3호
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• pp.91-97
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• 2007

Femtosecond laser micro-processing received much attention in the past decade. The nature of ultra-short light-matter interaction permits femtosecond laser to overcome the diffraction limit and realize precise micro-processing. The ultrahigh light intensity of the femtosecond laser allows sapece-selective microscopic modifications to materials based on multiphoton processes. In this paper, we review our recent research development on space-selective precipitation and control of functional crystals in glasses by an infrared femtosecond laser. The technique will open new possibilities in the fabrication of micro-optical components with various optical functions.

• 한국전기전자재료학회논문지
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• 제15권6호
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• pp.551-557
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• 2002

Carbon nitride films have been deposited on Si(100) substrate by a high voltage discharge plasma combined with laser ablation in a nitrogen atmosphere. The films were grown both with the without the presence of an assisting focused Nd:YAG laser ablation. The laser ablation of the graphite target leads to vapor plume plasma expending into th ambient nitrogen arc discharge area. X-ray photoelectron spectroscopy and Auger electron spectroscopy were used to identify the binding structure and the content of the nitrogen species in the deposited films. The nitrogen content of the films was found to increase drastically with an increase of nitrogen pressure. The surface morphology of the films was studied using a scanning electron microscopy. Data of infrared spectroscopy and x-ray photoelectron spectroscopy indicate the existence of carbon-nitrogen bonds in the films. The x-ray diffraction measurements have also been taken to characterize the crystal properties of the obtained films.

• 한국광학회지
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• 제10권1호
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• pp.15-20
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• 1999

레이저 프린터의 핵심부품 중 하나인 LSu(Laser Scanning Unit)를 구성하는 광학부품 및 각 부품들의 역할에 대해서 살펴보았고, 각 부품별로 기초설계를 한 후 Code-V를 사용하여 최적설계를 했다. 특히 f$\theta$렌즈 설게시 기존제품들을 비교.분석하여 설계에 반영했다. 본 논문에서는 LSU의 저가격화 및 소형화를 위해, 초점거리가 136mm인 2매의 플라스틱 f$\theta$렌즈로 구성된 LSU용 광학계를 설계하였다.

• 열처리공학회지
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• 제8권3호
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• pp.182-186
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• 1995

SCM440, which is widely used as the diesel engine piston of vessel, has been hardened by a $CO_2$ laser with the wavelength of $10.6{\mu}m$. Laser hardening experiment has been carried out for the condition of a laser power 1kW, the travel speed between 0.4 and 1.5m/min, and a rectangular-Gaussian beam. Residual stress has been measured by using middle point technique of half value width of X-ray diffraction method. It was found that the compressive residual stress with the range between 400 and 600MHz has distributed in the laser hardening zones and the tensile residual stress between 100 and 200MHz has distributed in the boundary of hardening zones.

• 한국레이저가공학회지
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• 제16권1호
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• pp.15-19
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• 2013

For numerical simulation of the deformation and residual stress development in metals during laser peening, the constitutive equations describing material behavior at various strain rates and plastic properties at high strain rate impact conditions are prerequisite. However, these parameters are often unknown for various engineering materials. In this study, the parameters of Johnson-Cook constitutive equation of duplex stainless steel were determined by comparing the residual stress profile predicted by numerical simulation using trial values and the measured residual stress profile with x-ray diffraction.

• 한국정밀공학회지
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• 제33권10호
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• pp.845-850
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• 2016

A direct laser lithography system is widely used to fabricate various types of DOEs (Diffractive Optical Elements) including lenses made as CGH (Computer Generated Hologram). However, a parametric study that uniformly and precisely fabricates the diffractive patterns on a large area (up to $200mm{\times}200mm$) has not yet been reported. In this paper, four parameters (Focal Position Error, Intensity Variation of the Lithographic Beam, Patterning Speed, and Etching Time) were considered for stabilization of the direct laser lithography system, and the experimental results were presented.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
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• pp.1030-1033
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• 2002

ZnO thin films on (100)p-type silicon substrates have been deposited by pulsed laser deposition(PLD) technique using an Nd:YGA laser with a wavelength of 266nm. The influence of the deposition parameters, such as oxygen pressure, substrate temperature and laser energy density variation on the properties of the grown film, was studied. The experiments were performed for substrate temperatures in the range of $200{\sim}500^{\circ}C$ and oxygen pressure in the range of $10^{-2}{\sim}10^2mTorr$. We investigated the structural, morphological and optical properties of ZnO thin films using X-ray diffraction(XRD), atomic force microscopy(AFM), photoluminescence(PL).

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집
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• pp.240-243
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• 2002

Carbon nitride films have been deposited on Si(100) substrate by a high voltage discharge plasma combined with laser ablation in a nitrogen atmosphere. The films were grown both with and without the Presence of an assisting focused Nd:YAG laser ablation. The laser ablation of the graphite target leads to vapor Plume plasma expending into the ambient nitrogen arc discharge area. X-ray photoelectron spectroscopy and Auger electron spectroscopy were used to identify the binding structure and the content of the nitrogen species in the deposited films. The surface morphology of the films was studied using a scanning electron microscopy Data of infrared spectroscopy and x-ray photoelectron spectroscopy indicate the existence of carbon-nitrogen bonds in the films. The x-ray diffraction measurements have also been taken to characterize the crystal properties of the obtain films.