• Korean Journal of Optics and Photonics
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• v.2 no.2
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• pp.59-66
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• 1991

Resonance angle and optimum thinckness of various thin metal films for surface plasmon resonance were calculated using an admittance diagram and optical constants and thickness of thin Ag films and Al films were determined by fitting the measured reflectance of surface plasmon resonance. Two wavelengths of an Ar ion laser were employed to select the unique optical constants which have the same thickness at two wavelengths. Also, when these films were exposed to the air, the shift of surface plasmon resonance was measured and the optical constants of modified thin films were determined.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.3
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• pp.209-212
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• 2012

In this paper, we have studied on the optimal design of the optical compensation film for the TN-LCDs. To have wide viewing angle panels, several methods such as multi-domain method, optical path method, and phase compensation method have been proposed. Among these methods, this paper focused on the phase compensation method. In the phase compensation method, the phase retardation generated from the optical birefringence for the off-axis incident is compensated by using optical films with refractive anisotropy. To compensate the phase retardation of the TN-LCDs, we have proposed design concept for the biaxial optical films and analyzed the optical performance for the proposed structures. The calculation of the dynamic motion of the liquid crystals was based on the Ericksen-Leslie theory and the optical performance of the TN-LCD was calculated from the Extended Jones Matrix Method. From the results, we have confirmed that the optical characteristics of the TN-LCDs with the biaxial films have been improved considerably compared with the TN-LCDs compensated by the combination of the uniaxial films.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.266-269
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• 2003

TFT LCD mode has some well-documented performance limitations, namely limited viewing angle, inversion of the gray scale levels and poor luminance efficiency because of the necessity of using crossed polarisers attached to the display cell. During the last few years many initiatives have been undertaken to solve these problems by incorporation birefringent films of various designs into the LCD module. Controlling the optical performance of LCDs often requires combination of liquid crystal material properties, cell parameters and optical films. Such optical films have traditionally been made with stretched polymer materials such as polycarbonate, but recently coated liquid crystalline materials have been used to give improved optical films which can greatly enhance the performance of LCDs. We have now developed reactive mesogen materials to add ultra-thin optical layers into the display structure, and these allow the potential for many new applications.

• Journal of Integrative Natural Science
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• v.6 no.4
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• pp.244-250
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• 2013

Three types of functionalized flexible optical composite films based on Bragg structure porous silicon interferometer have been successfully fabricated by casting a toluene solution of polystyrene onto the free-standing porous silicon. The optical properties of composite films are measured. Surface functionalization of porous silicon is determined by FT-IR measurement. Reflectance and transparence properties of composite films are measured for the possible application of tunable optical filter and indicate that the transmission peak occurred at the identical location where the reflection peak appeared.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.1
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• pp.1-7
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• 2005

Thin films of vanadium oxide(VO/sub x/) were deposited by r.f. magnetron sputtering from V₂O/sub 5/ target with oxygen/(oxygen+argon) partial pressure ratio of 0% and 8% and in situ annealed in vacuum at 400℃ for 1h and 4h. Crystal structure, chemical composition, molecular structure, optical and electrical properties of films were characterized through XRD, XPS, RBS, FTIR, optical absorption and electrical conductivity measurements. The films as-deposited are amorphous, but 0%O₂ films annealed for time longer than 4h and 8% O₂ films annealed for time longer than 1h are polycrystalline. As the oxygen partial pressure is increased the films become more stoichiometric V₂O/sub 5/. When annealed at 400℃, the as-deposited films are reduced to a lower oxide. The optical transmission of the films annealed in vacuum decreases considerably than the as-deposited films and the optical absorption of all the films increases rapidly at wavelength shorter than about 550nm. Electrical conductivity and thermal activation energy are increased with increasing the annealing time and with decreasing the oxygen partial pressure.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.7
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• pp.408-413
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• 2016

The dielectric thin films applied to multi-colored semitransparent thin film solar cells have been extensively studied. In this work, we prepared GeSbTe and GeTe chalcogenide thin films using magnetron sputtering, and investigated their optical and phase-change properties to replace the dielectric films. The changes of surface morphology, sheet resistance, and X-ray diffraction of the Te-based chalcogenide films support the fact that the amorphous stability of GeTe films is superior to that of GeSbTe films. While both amorphous GeSbTe and GeTe films thinner than 30 nm have optical transparency between 5% and 60%, GeTe films transmit more visible light than GeSbTe films. It is confirmed by computer simulation that the color of semitransparent silicon thin film solar cells can be adjusted with the addition of GeSbTe or GeTe films. Since it is possible to adjust the contrast of the solar cells by exploiting the phase-change property, the two kinds of chalcogenide films are anticipated to be used as an optical layer in semitransparent solar cells.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1992.05a
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• pp.101-104
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• 1992

In-doped CdS thin films have been deposited at 150$^{\circ}C$ by simultaneous thermal evaporation of CdS and In. Deposition rate and film thickness were 8A/sec and about 1um, respectively. Indium doping concentration of films varied as Indium source temperature from 500$^{\circ}C$ to 700˚. Properties of In-CdS films have been investigatied by measurements of electrical resistivity, Hall effect, X-ray diffraction and optical trasmission spectra. The conductivity of these films was always n-type. The resistivity, carrier concentration, mobility and optical band gap dependence on Indium source temperature are reported. Carrier concentration and mobility of In-CdS films increased with increasing Indium source temperature: then they decreased. The variation of the optical band gap of In-CdS thin films are related to carrier concentration.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.05a
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• pp.34.2-34.2
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• 2009

The silver sulphide (Ag2S) thin films have been chemically deposited from an alkaline medium (pH 8 to 10) by using a silver nitrate and thiourea as a Ag and S ion precursor sources. Ethylene Damine tetraacetic acid (EDTA) was used as a complexing agent. The effect of annealing atmosphere such as Ar, N2+H2S and O2 on the structural, morphological and optical properties of Ag2S thin films has been studied. The annealed films were characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM) and optical absorption techniques for the structural, morphological, and optical properties, respectively. XRD studies reveal that the as-deposited thin films are polycrystalline with monoclinic crystal structure, is converted in to silver oxide after air annealing. The surface morphology study shows that grains are uniformly distributed over the entire surface of the substrate. Optical absorption study shows the as-deposited Ag2S thin films with band gap energy of 0.92eV and after air annealing it is found to be 2.25 eV corresponding to silver oxide thin films.

• Korean Journal of Metals and Materials
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• v.50 no.11
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• pp.847-854
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• 2012

Al-doped ZnO (AZO) thin films were grown on quartz substrates by the sol-gel method. The effects of the Al mole fraction on the structural and optical properties of the AZO thin films were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), and UV-VIS spectroscopy. The particle size of the AZO thin films decreased with an increase in Al concentrations. The optical parameters, the optical band gap, absorption coefficient, refractive index, dispersion parameter, and optical conductivity, were studied in order to investigate the effects of Al concentration on the optical properties of AZO thin films. The dispersion energy, single-oscillator energy, average oscillator wavelength, average oscillator strength, and refractive index at an infinite wavelength of the AZO thin films were affected by the Al incorporation. The optical conductivity of the AZO thin films also increased with increasing photon energy.

• Journal of the Korean Society for Heat Treatment
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• v.28 no.2
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• pp.63-67
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• 2015

$TiO_2/Ag/TiO_2$ trilayer films were deposited with radio frequency (RF) and direct current (DC) magnetron sputtering onto the glass substrate to consider the influence of Ag interlayer on the optical properties of the films. The thickness of $TiO_2$ films was kept at 24 nm, while the thickness of Ag interlayer was varied as 5, 10, 15, and 20 nm. As-deposited $TiO_2$ single layer films show the optical transmittance of 66.7% in the visible wave-length region and the optical reflectance of 16.5%, while the $TiO_2$ films with a 15 nm thick Ag interlayer show the enhanced optical transmittance of 80.2% and optical reflectance of 77.8%. The carrier concentration was also influenced by Ag interlayer. The highest carrier concentration of $1.01{\times}10^{23}cm^{-3}$ was observed for a 15 nm thick Ag interlayer in $TiO_2/Ag/TiO_2$ films. The observed result means that an optimized Ag interlayer in $TiO_2/Ag/TiO_2$ films enhanced the structural and optical properties of the films.