• Title/Summary/Keyword: Optical materials

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Effects of Hydrogen Gas on the Optical Properties of Diamondlike Carbon Thin Films Prepared by Plasma Enhanced Chemical Vapor Deposition (플라즈마 화학증법에 의해 형성된 Diamondlike Carbon 박막의 광학적 특성에 미치는 수소가스의 영향)

  • Kim, Han-Do;Ju, Seung-Gi
    • Korean Journal of Materials Research
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    • v.4 no.2
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    • pp.152-158
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    • 1994
  • Diamondlike carbon thin film have been fabricated using methane as a reactive gas by plasma enhanced chemical vapor deposition. Effects of hydrogen gas on the optical properties of the thin film has been investigated. When the hydrogen was used as a secondary gas, the role of hydrogen changed with deposition power unlike inert gases such as Ar and He. From the changes of optical band gap and FT-IR analysis, it was predicted that the chemical etching, sputtering of C-H bond by hydrogen and the implantation of hydrogen into the thin film could occur. The validity of the possibilities was confirmed by examining the effect of secondary gases such as Ar and He.

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Characteristics of Diamondike Carbon thin Films by Low Discharging Frequency(450KHz) PECVD (저주파수(450 KHz) PECVD에 의한 Diamondlike Carbon박막의 특성)

  • Kim, Han-Ju;Ju, Seung-Gi
    • Korean Journal of Materials Research
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    • v.4 no.2
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    • pp.227-232
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    • 1994
  • Diamondlike carbon thin film has been fabricated with low discharging frequency, 450KHz by plasma enhanced chemical vapor deposition. Its physical properties such as optical band gap, microhardness and internal stress have been compared with 13.56MHz film. Optical band gap of 450KHz DLC thin film was less than 13.56MHz film and it was found that C-H bond concentration and total hydrogen contents in the film decreased greatly as the result of FT-IR and CHN analysis. Also, when DLC thin film was fabricated with low discharging frequency, it was expected that the adhesion of the film to the substrate was improved by the great decrease of internal stress without any considerable decrease of microhardness.

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Characteristics of ITO Films Grown on an Oxygen Plasma Treated Glass Substrate (유리기판에 O2 플라즈마 표면처리 후 제작된 ITO 박막의 특성)

  • Chae, Hong-Chol;Hong, Joo-Wha
    • Korean Journal of Metals and Materials
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    • v.50 no.7
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    • pp.545-548
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    • 2012
  • The optical and electronic properties of Indium Tin Oxide (ITO) thin films deposited on a RF-plasma treated glass substrate were investigated by X-Ray Photoelectron Spectroscopy (XPS), Ultra-violet Photoelectron Spectroscopy (UPS), Reflected Electron Energy Loss Spectroscopy (REELS). The modification of glass substrates was carried out by varying the time of the plasma surface treatment in an oxygen atmosphere. The focus of this research was to examine how the optical and electronic properties of ITO thin films change with the plasma treatment time. The surface energy increased since the carbon bonds were removed from the surface after the glass substrate received the surface treatment. The ITO thin films produced on the glass substrate with surface treatment showed that the high optical transmittance was approximately 85%. The measured band gap energy was as high as 3.23 eV when the plasma treatment time was 60 s and the work function after the treatment was increased by 0.5 eV in comparison to that before the treatment of 60 s. The ITO thin film exhibited an excellent sheet resistance of $2.79{\Omega}/{\Box}$. We found that the optical and electronic properties of ITO thin films can be improved by RF-plasma surface treatment.

Effect of the Cu Bottom Layer on the Properties of Ga Doped ZnO Thin Films

  • Kim, Dae-Il
    • Transactions on Electrical and Electronic Materials
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    • v.13 no.4
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    • pp.185-187
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    • 2012
  • Ga doped ZnO (GZO)/copper (Cu) bi-layered film was deposited on glass substrate by RF and DC magnetron sputtering and then the effect of the Cu bottom layer on the optical, electrical and structural properties of GZO films were considered. As-deposited 100 nm thick GZO films had an optical transmittance of 82% in the visible wavelength region and a sheet resistance of 4139 ${\Omega}/{\Box}$, while the GZO/Cu film had optical and electrical properties that were influenced by the Cu bottom layer. GZO films with 5 nm thick Cu film show the lower sheet resistance of 268 ${\Omega}/{\Box}$ and an optical transmittance of 65% due to increased optical absorption by the Cu metallic bottom layer. Based on the figure of merit, it can be concluded that the thin Cu bottom layer effectively increases the performance of GZO films as a transparent and conducting electrode without intentional substrate heating or a post deposition annealing process.

Analytical approximation of optical force on a perfectly reflecting sphere: ray-optics regime

  • Kim, Sang Bok;Song, Dong Keun
    • Particle and aerosol research
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    • v.14 no.1
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    • pp.1-8
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    • 2018
  • The optical force on a perfectly reflecting sphere in a ray-optics regime is considered. With the assumption of geometric optics and a sphere smaller than the minimum waist of the illuminating beam, closed-form analytic expressions of the optical force are derived. Both axial and radial forces are expressed by a modified Bessel function of the first kind. The derived analytic expressions are compared to precise numerical computations of the exact optical force equations derived previously. In addition the error due to the small sphere assumption is estimated analytically.

Optical characteristics of GaN-based quantum structures

  • 조용훈
    • Proceedings of the Materials Research Society of Korea Conference
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    • 2003.11a
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    • pp.22-22
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    • 2003
  • Studies on the optical properties related to the built-in internal field and the carrier localization present in various GaN-based structures are essential not only for the physical interest but in designing practical visible and ultraviolet light emitting device applications with better performance and quantum efficiency. We report on the optical characteristics of various dimensional GaN-based structures such as (i) GaN self-assembled quantum dots grown in Stranski-Krastanov mode (OD), vertically-aligned GaN nanorods (1D), graded-In-content InGaN quantum wells (2D), laterally-overgrown GaN pyramids (3D), and GaN epilayers grown on various substrates. We used a wide variety of optical techniques, such as photoluminescence (PL), PL excitation, micro-PL, cathodoluminescence, optically-pumped stimulated emission, and time-resolved PL spectroscopy. An overview and comparison of the optical characteristics of the above GaN-based structures will be given.

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Development of Composite Optical Bench for Earth observation Satellite (복합재료를 사용한 지구관측위성 광학탑재체 지지구조물 개발)

  • Kim, Jin-Hee;Kim, Kyung-Won;Lee, Ju-Hun;Jin, Ik-Min;Yoon, Gil-Won
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2005.11a
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    • pp.207-210
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    • 2005
  • In this paper, technical issues for an optical bench of high precision LEO Earth observation satellite are described. The optical bench should be stable for thermal and dynamic environment. In this point of view, an intermediate type of optical bench is developed. Thermal deformation analysis and modal analysis are performed for two types of FE model. Modal test are performed to verify the analysis results. The test results fit well the analysis results.

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Nano-turning of single crystal silicon (단결정 실리콘의 초정밀가공)

  • 김건희;도철진;홍권희;유병주;원종호;박상진;안병민
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2000.11a
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    • pp.939-942
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    • 2000
  • Single point diamond turning technique for optical crystals is reported in this paper. The main factors influencing the machined surface quality are discovered and regularities of machining process are drawn. Optical crystals have found more and more important applications in the field of modern optics. Optical crystals are mostly brittle materials of poor machinability. The traditional machining method is polishing which has many shortcomings such as low production efficiency, poor ability to be automatically controlled and edge effect of the workpiece. The purpose of our research is to find the optimum machining conditions for ductile cutting of optical crystals and apply the SPDT technique to the manufacturing of ultra precision optical components of brittle material.

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A Study on the Stabilization Scheme of Optical Source for Precision Measurement (정밀측정을 위한 안정된 광원에 관한 연구)

  • 김지대;서호성;이동주
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2003.04a
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    • pp.265-271
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    • 2003
  • This study is for the stable optical source in order to get the precision measurement, which contributes to help the laser frequency and the output to be settled. The laser optical frequency is changed by the length of resonance cavity. The length variation of the laser resonance amplitude is affected by the thermal expansion of that system. So, we try not only to adjust the temperature of the laser tube using the heater for fine length of resonance cavity, but also to maintain the fixed temperature of the resonance cavity for outputting the safe laser optical frequency. Therefore, we must take materials with the thermal expansion of the supporting system, which is closer to it of the laser resonance cavity. Using the materials, we can promote to stabilize the temperature of it. In advance, we also plan to get the settlement of the laser frequency and the output in the long km, optimizing and stabilizing the system.

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Effect of Electron Irradiation on the Structural Electrical and Optical Properties of ITO/ZnO Thin Films (전자빔 조사에너지에 따른 ITO/ZnO 적층박막의 구조적, 전기적, 광학적 특성 변화)

  • Kim, Sun-Kyung;Kim, Daeil
    • Journal of the Korean Society for Heat Treatment
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    • v.27 no.5
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    • pp.225-229
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    • 2014
  • The influence of electron irradiation energy(eV) on the structural, electrical and optical properties of ITO/ZnO bi-layered films prepared with RF magnetron sputtering has been investigated. The ITO/ZnO show the lowest resistivity of $2.8{\times}10^{-4}{\Omega}cm$. The optical transmittance in a visible wave length region also increased with the electron irradiation energy. The film irradiated at 900 eV shows 82---- of optical transmittance in this study. By comparison of figure of merit, it was observed the optical transmittance and electrical resistivity of the films were dependent on the electron irradiation energy and optoelectrical performance of ITO/ZnO film is improved with electron irradiation.