• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11b
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• pp.480-483
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• 2001

Epitaxial rutile-$TiO_2$ and anatase-$TiO_2$ films were grown at $800^{\circ}C$ on $Al_2O_3$ (1102) and $LaAlO_3$ (001), respectively, using pulsed laser deposition. The formation of different phases on different substrates could be qualitatively explained by the atomic arrangements at the interfaces. We also successfully deposited epitaxial rutile-$TiO_2$ and anatase-$TiO_2$ films on conductive $RuO_2$ and $La_{0.5}Sr_{0.5}CoO_{3}$ electrodes, respectively. Using a Kelvin probe, we measured the photovoltaic properties of these multilayer structures. A rutile-$TiO_2$ film grown on $RuO_2$ showed a very broad peak in the visible light region. An epitaxial anatase-$TiO_2$ film grown on $La_{0.5}Sr_{0.5}CoO_{3}$ showed a strong peak with a threshold energy of 3.05 eV.

• Journal of Magnetics
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• v.12 no.4
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• pp.144-148
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• 2007

We report on the observation of p-type conductivity and ferromagnetism in diluted magnetic semiconductor $(Zn_{0.97}Mg_{0.01}Mn_{0.02})O:P$ films grown on $SiO_2/Si$ substrates by pulsed laser deposition. The p-type conduction with hole concentration over $10^{18}cm^{-3}$ is obtained by codoping of Mg and P followed by rapid thermal annealing in an $O_2$ atmosphere. Structural and compositional analyses for the p-type $(Zn_{0.97}Mg_{0.01}Mn_{0.02})O:P$ films annealed at $800^{\circ}C$ indicates that highly c-axis oriented homogeneous films were grown without any detectable formation of secondary phases. The films were found to be transparent in the visible range. The magnetic measurements clearly revealed an enhancement of room temperature ferromagnetism by p-type doping.

• Proceedings of the KIEE Conference
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• 2006.10a
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• pp.46-47
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• 2006

Ga-doped ZnO nanowires have been synthesized by pulsed laser deposition (PLD) in furnace on gold coated (0001) sapphire substrates. The effect of repetition rate on structural and optical properties of Ga-doped ZnO nanowires are investigated. By controlling repetition rate, the diameter of nanowires is varied between about 60 and 100 nm, and the length of nanowires is varied between about 2 and 4 um. The X-ray diffraction (XRD) reveals the structural defects induced by the Ga doping. The room temperature photoluminescence (PL) spectra of Ga-doped ZnO nanowires show strong UV emission between 382.394 and 385.279 nm with negligible visible emission.

• ETRI Journal
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• v.26 no.1
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• pp.38-44
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• 2004

Searching for systems of self-assembled monolayers (SAMs) that can be used as templates for chemical lithography, we found that nitro groups on aromatic SAMs are selectively converted on Ag to amino groups by irradiation with a visible laser. 4-nitrobenzenethiol on Ag was thus converted to 4-aminobenzenethiol by irradiating it with an $Ar^+$ laser. This was evident from surface-enhanced Raman scattering (SERS) as well as from a coupling reaction forming amide bonds. The surface-induced photoreaction allowed us to prepare patterned binary monolayers on Ag that showed different chemical reactivities. Using the binary monolayers as a lithographic template, we induced site-specific chemical reactions, such as the selective growth of biominerals on either the nitro- or amine-terminated regions by adjusting the crystal-growth conditions. We also demonstrated that patterned, amine-terminated monolayers can be fabricated even on gold by using silver nanoparticles as photoreducing catalysts.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.480-483
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• 2001

Epitaxial rutile-TiO$_2$ and anatase-TiO$_2$ films were grown at 80$0^{\circ}C$ on $Al_2$O$_3$ (1102) and LaAlO$_3$ (001), respectively, using pulsed laser deposition. The formation of different phases on different substrates could be qualitatively explained by the atomic arrangements at the interfaces. We also successfully deposited epitaxial rutile-TiO$_2$ and anatase-TiO$_2$ films on conductive RuO$_2$ and La$_{0.5}$Sr$_{0.5}$CoO$_3$ electrodes, respectively Using a Kelvin probe, we measured the photovoltaic properties of these multilayer structures. A rutile-TiO$_2$ film grown on RuO$_2$ showed a very broad peak in the visible light region. An epitaxial anatase-TiO$_2$ film grown on La$_{0.5}$Sr$_{0.5}$CoO$_3$ showed a strong peak with a threshold energy of 3.05 eV 3.05 eV

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.1884-1886
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• 2005

KrF 펄스 레이저 증착법(pulsed laser deposition: PLD)으로 ZnO 박막을 증착하여 평판 디스플레이 소자 구동용 박막 트랜지스터(thin film transistor) 소자를 제작하였다. 전도성이 높은 실리콘웨이퍼(c-Si, 하부전극) 기판 위에 LPCVD 법으로 silicon nitride 박막을 절연막으로 형성하고, 다양한 공정 조건에서 펄스 레이저 증착법으로 제작한 ZnO 박막을 증착하여 채널층으로 하였으며, Al 박막을 증착하고 패터닝하여 소스 및 드레인 전극으로 하였다. ZnO 박막의 증착 시에 기판 온도를 다양하게 조절하고 산소 분압을 변화시켜 ZnO 박막의 특성을 조절하였다. 제작된 박막의 표면특성은 AFM(atomic force microscopy)로 분석하고, 결정특성은 XRD(X-ray diffraction)로 조사하였다. ZnO 박막의 전기적 특성은 Hall-van der Pauw 법으로 측정하였고, 광학 투과도(optical transparency)를 UV-visible photometer로 조사하였다. ZnO-TFT 소자는 $10^6$ 수준의 on-off ratio와 $2.4{\sim}6.1cm^2/V{\cdot}s$의 전계효과이동도(field effect mobility)를 보였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.262-263
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• 2007

Effect of co-doping on optical and electrical properties of $SnO_2$ based thin films were studied. $SnO_2$ ceramic targets with up to 50mol% $CuSb_2O_6$ were prepared by sintering mixed-oxide compact in the temperature range of $1100^{\circ}C{\sim}1300^{\circ}C$ in air. Thin films were then deposited onto glass substrates by pulsed laser deposition where substrate temperature was maintained in the range of $500{\sim}650^{\circ}C$ with oxygen pressure of 3m~7.5mTorr and energy density of $1Jcm^{-2}$. It was found that with the increase amount of dopant, the electrical properties of thin films tended to improve with the smallest resistivity value obtained at about 8mol% doping, further increase, however, usually impaired the optical transmission in the visible range.

• Journal of Korea Multimedia Society
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• v.19 no.8
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• pp.1225-1235
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• 2016

This paper presents a method for computer-assisted slide presentation using vision-based gesture recognition. The proposed method consists of a sequence of steps, first detecting a hand in the scene of projector beam, then estimating the smooth trajectory of a hand or a pointing finger using Kalman Filter, and finally interfacing to an application system. Additional slide navigation control includes moving back and forth the pages of the presentation. The proposed method is to help speakers for an effective presentation with natural improved interaction with the computer. In particular, the proposed method of using finger pointing is believed to be more effective than using a laser pointer since the hand, the pointing or finger are more visible and thus can better grab the attention of the audience.

• Korean Journal of Optics and Photonics
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• v.2 no.4
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• pp.179-185
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• 1991

Twyman-Green interferometer is developed for assessment of IR optical system performance. Light source is $CO_2$ gas laser which has 10.6$\mu \textrm m$ wavelength. The light beam is expanded to 2.5 cm dia by Ge lens and splitted by ZnSe parallel plane plate. One of the beams is reflected by refernce mirror which is operated PZT. The fringe will be detected by a pyro-electric vidicon camera and displayed by a CRT monitor. Here, the IR firinge is recorded on the thermal paper. In visible region, the light source is He-Ne laser. The fringe is detected by a CCD camera and displayed by the CRT monitor. The intensity of the fringe is digitized by a image card and processed by a PC. The wavefront aberration function, PSF and OTF are calculated. The results are displayed in 3-D graphs on the monitor or printed out by a line printer.

• Korean Journal of Optics and Photonics
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• v.13 no.2
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• pp.123-127
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• 2002

We have measured the wavelengths of the absorption lines of the $^{13}$ C$_2$H$_2$molecule by using a wavelength meter calibrated against the national optical frequency standard (iodine Stabilized He-Ne Laser, KRISS-R701) in the visible wavelength region. To measure the absolute wavelengths of the absorption lines, the frequency of the laser has been stabilized in the peaks and the sides of the absorption lines of $^{13}$ C$_2$H$_2$. Also, we have proposed the development of a frequency standard source of ITU-T grid using stabilization in the sides of the absorption lines of $^{13}$ C$_2$H$_2$.