• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.532-534
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• 2000

Si thin films on p-type (100) Si substrate have been fabricated by pulsed laser deposition technique using a Nd:YAG laser. The pressure of the environmental gas during deposition was varied from 1 to 3 Torr. After deposition, Si thin film has been annealed again at nitrogen ambient. Strong violet-indigo photoluminescence have been observed from Si thin film annealed in nitrogen ambient gas. As increasing environmental gas pressure, weak green and red emissions from annealed Si thin films also observed by photoluminescence.

• Proceedings of the Korean Society of Laser Processing Conference
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• 2003.05a
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• pp.92-95
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• 2003

• Proceedings of the Korean Society of Laser Processing Conference
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• 2001.05a
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• pp.11-13
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• 2001

• Journal of the Korean Ceramic Society
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• v.31 no.3
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• pp.312-320
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• 1994

Effect of the laser shot number on the particulates density of the pulsed laser deposited YBa2Cu3O7-x thin films and the laser irradiated surface morphology of the YBa2Cu3O7-x bulk target have been investigated. Until 100 laser shots of cumulative irradiation, the films has the particulates density of ~103 mm-2. However, after 100 laser shots, the density was increased more than 10 times. This results has been explained by the change of particulate ejection path with the development of conical structure at the target surface.

• Proceedings of the KWS Conference
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• 2000.04a
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• pp.139-143
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• 2000

Laser beam weldability of Zircaloy-4 was investigated using a pulsed Nd:YAG laser of 550W average power. Mechanical properties and microstructure of laser butt welded Zircaloy-4 test specimens were examined. The influence of laser generated during laser welding was analyzed and optimum laser welding parameters were investigated.

• Journal of Veterinary Clinics
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• v.27 no.6
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• pp.647-651
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• 2010

The advantages of the $CO_2$ laser are offset by the delay in laser wound healing secondary to thermal damage. To minimize the undesirable thermal damage of the $CO_2$ laser, investigators have developed technical advances in the delivery system of the laser energy. This study compared tissue healing of the continuous and the pulsed modes $CO_2$ laser wounds in an animal surgery model. Five healthy Landrace and Yorkshire mixed breeds of both genders were used (45-51 kg, 4-6 months old, three males and two females). A full thickness wound of skin ($2{\times}2{\times}2cm^2$) was made over on the each pig's both sides of dorsal midline at 0, 7, 14, and 18 days. The wounds created at 18, 14, 7 and 0 days were named post-wounding day (PWD) 3, 7, 14 and 21, respectively. In each pig, one wound (left side) was treated pulsed $CO_2$ laser and the other wound (right side) was treated continuous wave $CO_2$ laser. Each wound was closed with two interrupted suture of 3-0 sutures. At 21 days after initial wounding, each wound was taken for histological evaluations. The degrees of reepithelialization were performed more prominently in the pulsed mode group than in the continuous mode group. The degrees of granulation were greater significantly in pulsed mode group than those in the continuous mode on PWD 3 (p < 0.05). The degrees of fibroblasts in the pulsed mode group were greater significantly in comparison to those in the continuous mode group on PWD 7, (p < 0.05). In conclusion, reepithelialization, granulation and fibroblasts in the pulsed mode group were greater markedly in comparison to those in the continuous mode group. It was considered that pulsed mode $CO_2$ laser was more suitable for the skin incision than the continuous mode $CO_2$ laser.

• Laser Solutions
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• v.14 no.3
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• pp.7-11
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• 2011

As an active emission display using emissive polymer has had much attention recently, needs for a selective patterning of emissive layer for those displays have been increased abruptly. Therefore, the various laser sources in terms of its wavelength has been used for laser direct patterning. In this work, the feasibility of those processes is examined using numerical analysis and the experimental investigation. A sample has multi-layered structure, emissive polymer on aluminum which is deposited on a glass substrate. Key factors for optimizing the laser patterning of the emissive polymer are considered into the control of ablation products, large-sized particle, and the choice of the appropriate wavelength for minimizing the heat affected zone and the remnant layer.

• Journal of the Optical Society of Korea
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• v.13 no.1
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• pp.65-74
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• 2009

Device quality indium tin oxide (ITO) films are deposited on glass substrates and ultra-thin diamond-like carbon films are deposited as a buffer layer on ITO by a pulsed Nd:YAG laser at 355 nm and 532 nm wavelength. ITO films deposited at room temperature are largely amorphous although their optical transmittances in the visible range are > 90%. The resistivity of their amorphous ITO films is too high to enable an efficient organic light-emitting device (OLED), in contrast to that deposited by a KrF laser. Substrate heating at $200^{\circ}C$ with laser wavelength of 355 nm, the ITO film resistivity decreases by almost an order of magnitude to $2{\times}10^{-4}\;{\Omega}\;cm$ while its optical transmittance is maintained at > 90%. The thermally induced crystallization of ITO has a preferred <111> directional orientation texture which largely accounts for the lowering of film resistivity. The background gas and deposition distance, that between the ITO target and the glass substrate, influence the thin-film microstructures. The optical and electrical properties are compared to published results using other nanosecond lasers and other fluence, as well as the use of ultra fast lasers. Molecularly doped, single-layer OLEDs of ITO/(PVK+TPD+$Alq_3$)/Al which are fabricated using pulsed-laser deposited ITO samples are compared to those fabricated using the commercial ITO. Effects such as surface texture and roughness of ITO and the insertion of DLC as a buffer layer into ITO/DLC/(PVK+TPD+$Alq_3$)/Al devices are investigated. The effects of DLC-on-ITO on OLED improvement such as better turn-on voltage and brightness are explained by a possible reduction of energy barrier to the hole injection from ITO into the light-emitting layer.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.9
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• pp.1105-1111
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• 2011

The objective of this study is to investigate the influence of surface roughness on the morphology of aluminum 6061-T6 alloy after irradiation with a Nd:YAG pulsed laser. The test specimen was prepared by a polishing process using a diamond paste ($1{\mu}m$) and emery polishing papers (#100, #220, #600, #2400) to obtain different initial surface roughness. After irradiation with ten pulsed-laser shots, the surface morphology was examined by using scanning electron microscopy (SEM), optical microscopy (OM), and atomic force microscopy (AFM). The diameter of the melted zone increased with the surface roughness because the multiple reflections and absorption of the laser beam occurred on the surface because of the surface roughness, so that the absorptance of the laser beam changed. This result was verified using the relative absorptance calculated from the diameter of the melted zone with the surface roughness and the diameter increased with the average surface roughness.

• Electrical & Electronic Materials
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• v.8 no.3
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• pp.285-290
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• 1995

High quality $Y_{1}$Ba$_{2}$Cu$_{3}$$O_{7-x}$ thin films have been fabricated by pulsed Nd:YAG laser deposition using an unusual 'off-axis' target-substrate geometry. Various properties of superconducting $Y_{1}$Ba$_{2}$Cu$_{3}$$O_{7-x}$ thin films have been studied systematically as a function of oxygen pressure during the deposition, in both 'on-axis' and the unusual 'off-axis' target substrate geometries. In the 'off-axis' geometry, one can completely eliminate the so-called 'laser droplets' from the film surface and thus obtain smooth high quality films. It is found that films with optimum structural and electrical properties are obtained at a lower oxygen pressure range during the 'off-axis' deposition when compared with that required in the 'on-axis' deposition geometry.