• Title/Summary/Keyword: Optical Properties

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Droplet Size Distribution Effect on the Electro-Optical Properties of Emulsion Type Polymer Dispersed Liquid Crystal (에멀전 방식의 고분자 분산형 액정의 전기 광학 특성에 미치는 액적 크기 분포의 영향)

  • Yoo, Hee Sang;Oh, Nam-Seok;Yan, Jin;Kwon, Soon-Bum
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.28 no.7
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    • pp.439-445
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    • 2015
  • We established the emulsion method using membrane filter with precise control of LC droplet distribution in PDLC. PDLC cells with various LC droplet size distributions such as single droplet sizes of $1.0{\mu}m$, $1.9{\mu}m$ and $3.5{\mu}m$, the mixture of two different LC droplet sizes and the mixture of three different LC droplet sizes were fabricated and the electro-optical properties of the emulsion type PDLC cells with various droplet size distribution were investigated. In the appropriate droplet size range, the PDLCs with the single droplet sizes distributions have good electro optical properties than those with the mixture of three different LC droplet sizes. In addition, the PDLC cells with the mixture of two different LC droplet sizes have the better electro optical properties than those with single droplet sizes distribution. The PDLC cell with dual droplet size distribution of $1.0+1.9{\mu}m$ shown the best electro optical properties than the PDLC cells with other size distributions. This method enabled us to find the proper LC droplet size distribution for achieving both high transmittance and contrast ratio.

Electrical and Optical Properties of Al-doped ZnO Films Deposited by Atomic Layer Deposition (Atomic Layer Deposition법에 의한 Al-doped ZnO Films의 전기적 및 광학적 특성)

  • An, Ha-Rim;Baek, Seong-Ho;Park, Il-Kyu;Ahn, Hyo-Jin
    • Korean Journal of Materials Research
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    • v.23 no.8
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    • pp.469-475
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    • 2013
  • Al-doped ZnO(AZO) thin films were synthesized using atomid layer deposition(ALD), which acurately controlled the uniform film thickness of the AZO thin films. To investigate the electrical and optical properites of the AZO thin films, AZO films using ALD was controlled to be three different thicknesses (50 nm, 100 nm, and 150 nm). The structural, chemical, electrical, and optical properties of the AZO thin films were analyzed by X-ray diffraction, X-ray photoelectron spectroscopy, field-emssion scanning electron microscopy, atomic force microscopy, Hall measurement system, and UV-Vis spectrophotometry. As the thickness of the AZO thin films increased, the crystallinity of the AZO thin films gradually increased, and the surface morphology of the AZO thin films were transformed from a porous structure to a dense structure. The average surface roughnesses of the samples using atomic force microscopy were ~3.01 nm, ~2.89 nm, and ~2.44 nm, respectively. As the thickness of the AZO filmsincreased, the surface roughness decreased gradually. These results affect the electrical and optical properties of AZO thin films. Therefore, the thickest AZO thin films with 150 nm exhibited excellent resistivity (${\sim}7.00{\times}10^{-4}{\Omega}{\cdot}cm$), high transmittance (~83.2 %), and the best FOM ($5.71{\times}10^{-3}{\Omega}^{-1}$). AZO thin films fabricated using ALD may be used as a promising cadidate of TCO materials for optoelectronic applications.

Optical and mechnical properties of ${Ta_2}{O_5}$ optical thin films by ion assisted deposition (이온 보조 증착한 ${Ta_2}{O_5}$ 광학 박막의 광학적 및 기계적 특성 분석)

  • 류태욱;김동진
    • Korean Journal of Optics and Photonics
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    • v.11 no.3
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    • pp.147-151
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    • 2000
  • We deposited the ion assisted ${Ta_2}{O_5}$ films and conventional thermal evaporated ${Ta_2}{O_5}$ films by using electron beam gun, and measured the optical properties and mechanical properties of the fabricated films according to the evaporation conditions. In the case of the TazOs films by oxygen ion assisted deposition with the anode voltage of 120 V, and current density of $50~500\muA/cm^2$, the refractive index exhibited 2.15 which was higher than the conventionally deposited film index 1.94 and the tensile stress exhibited $5.0\times10^8 dyne/cm^2$ which was lower than $7.0\times10^8 dyne/cm^2$. This properties coincided with the optical and mechanical properties of the films deposited at the elevated substrate temperature of $230^{\circ}C$. In the case of the argon ion assisted films the tensile stress was decreased but the absorption existed at the short wavelength in the visible spectral region. And all the fabricated films were found to be amorphous by the X-ray diffraction analysis. lysis.

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Single crystals growth and properties of $LiNbO_3$ doped with MgO or ZnO : (II) The electrical and optical properties (MgO 또는 ZnO를 첨가한 $LiNbO_3$단결정 성장 및 특성 : (II) 전기적 및 광학적 특성)

  • Cho, Hyun;Shim, Kwang-Bo;Auh, Keun-Ho
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.6 no.4
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    • pp.532-542
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    • 1996
  • The electrical and optical properties of the annealed $LiNbO_{3}$ single crystal with congruently melting composition and MgO or ZnO doped $LiNbO_{3}$ single crystal grown by the FZ method. The electrical and optical properties such as electrical conductivity, dielectric constant (Curie temperature), electro-mechanical coupling factor, optical transmittance and refractive indices of the grown crystals were measured and the nonlinear refractive indices of the grown crystals were calculated theoretically. The doping effects of MgO and ZnO were investigated by comparing the electrical and optical properties of the undoped $LiNbO_{3}$ single crystal and those of the $LiNbO_{3}$ single crystals doped with MgO or ZnO.

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