• Title/Summary/Keyword: EOU

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Effects of Various Deposition Rates of Al2O3 Gate Insulator on the Properties of Organic Thin Film Transistor (알루미늄 옥사이드 절연층의 증착율이 유기박막 트랜지스터의 특성에 미치는 영향)

  • Choi, Kyung-Min;Hyung, Gun-Woo;Kim, Young-Kwan;Choi, Eou-Sik;Kwon, Sang-Jik
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.22 no.12
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    • pp.1063-1066
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    • 2009
  • In this study, we fabricated pentacene organic thin film trasistors(OTFTs) which used aluminum oxide as the gate insulator. Aluminum oxide for OTFTs was deposited on glass substrate with a different deposition rate by E-beam evaporation. In case of the deposition rate of $0.1\;{\AA}$, the fabricated aluminum oxide gate insulating OTFT showed a threshold voltage of -1.36 V, an on/off current ratio of $1.9{\times}10^3$ and field effect mobility $0.023\;cm^2/V_s$.

Fabrication of Sputtered Gated Silicon Field Emitter Arrays with Low Gate Leakage Currents by Using Si Dry Etch

  • Cho, Eou Sik;Kwon, Sang Jik
    • Transactions on Electrical and Electronic Materials
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    • v.14 no.1
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    • pp.28-31
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    • 2013
  • A volcano shaped gated Si-FEA (silicon field emitter array) was simply fabricated using sputtering as a gate electrode deposition and lift-off for the removal of the oxide mask, respectively. Due to the limited step coverage of well-controlled sputtering and the high aspect ratio in Si dry etch caused by high RF power, it was possible to obtain Si FEAs with a stable volcano shaped gate structure and to realize the restriction of gate leakage current in field emission characteristics. For 100 tip arrays and 625 tip arrays, gate leakage currents were restricted to less than 1% of the anode current in spite of the volcano-shaped gate structure. It was also possible to keep the emitters stable without any failure between the Si cathode and gate electrode in field emission for a long time.

Effects of Photon Energy Spectrum on the Photocurrent of Hydrogenated Amorphous Silicon Thin Film Transistor by Using Frequency Filters

  • Cho, Eou Sik;Kwon, Sang Jik
    • Transactions on Electrical and Electronic Materials
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    • v.14 no.1
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    • pp.16-19
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    • 2013
  • Frequency filters with various filtering wavelengths were used in the photoelectric characterization of hydrogenated amorphous silicon thin film transistor (a-Si:H TFT) and the experimental results were described and analyzed in terms of the photon energy spectral characteristics calculated from the integration of the photon energy and the spectral intensity of transmitted backlight through the filters at each wavelength. From the comparison of the photocurrents and the calculated photon energy spectrums for the filtered ranges of wavelength, it was possible to conclude that the photocurrents are closely related to the photon energy spectrums of the backlight.

Improvement in the Setup of the Inline Sputter System and the ITO Sputtering Process by Measuring and Controlling the Base Vacuum Level

  • Ahn, Min-Hyung;Cho, Eou-Sik;Kwon, Sang-Jik
    • Journal of Information Display
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    • v.9 no.4
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    • pp.15-20
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    • 2008
  • A DC-magnetron inline sputter was established, and the influence of the base pressure on the structural characteristics of the ITO thin films was studied. When the inline sputter system was established and operated for ITO sputtering, its initial vacuum level did not go below $5\times10^{-6}$ torr. The vacuum leak test was conducted by measuring t he elapsed time until the vacuum level reached $1\times10^{-6}$ torr. The base pressure was successfully maintained at $1\times10^{-6}$ torr for 900 min, and the uniformity of the ITO film that had been deposited at this pressure significantly improved.

A Study on the Impact of Quality Factors on the Easy of use and Usefulness of Mobile Games (사용자의 사용용이성 및 유용성에 영향을 미치는 모바일 게임 콘텐츠 품질요인에 관한 연구)

  • Han, Hui-Seon;Lee, Jae-Gwon
    • 한국디지털정책학회:학술대회논문집
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    • 2006.06a
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    • pp.409-417
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    • 2006
  • This study first tries to investigate factors that determine the quality of mobile game contents. Base on the information and information system-related studies, our research proposes to show the relationship among the quality of mobile game contents, the level of perceived easy of use and the perceived usefulness. Mobile game contents service providers can get insight on factors that should be considered to improve the quality of contents services. Also, the research findings provide a clue on the success of mobile game service.

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ITO Wet Etch Properties in an In-line Wet Etch/Cleaning System by using an Alternating Movement of Substrate (기판의 왕복 운동을 이용한 인라인 식각세정장치 내 ITO 식각특성)

  • Hong, Sung-Jae;Kwon, Sang-Jik;Cho, Eou-Sik
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.21 no.8
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    • pp.715-718
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    • 2008
  • An in-line wet etch/cleaning system was established for the research and development in wet etch process. The system was equipped with a reverse moving system for the reduction in the size of the in-line wet etch/cleaning system and it was possible for the glass substrate to be moved back and forth and alternated in a wet etch bath. For the comparison of the effect of the normal motion and that of the alternating motion on the in-line wet etch process, indium tin oxide(ITO) pattern was obtained through both wet etch process conditions. The results showed that the alternating motion is not inferior to the normal motion in etch rate and in etch uniformity. It is concluded that the alternating motion is possible to be applied to the in-line etch process.

Characteristics of Laser Direct Patterned Indium Tin Oxide Layer by Overlapping Rates of Laser Beam

  • Li, Zhao-Hui;Ahn, Min-Hyung;Choi, Kyung-Min;Im, Seung-Hyeok;Jung, Kyung-Seo;Cho, Eou-Sik;Kwon, Sang-Jik
    • 한국정보디스플레이학회:학술대회논문집
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    • 2009.10a
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    • pp.1496-1499
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    • 2009
  • A diode-pumped Nd:$YVO_4$ laser was used to obtain indium tin oxide (ITO) patterns on glass substrate with various overlapping rates. The results showed that the overlapping rate of laser beam influences on the edge structure of ITO pattern and the surface roughness of ablated groove bottom. At a laser repetition rate of 40 kHz, the optimized condition of overlapping rate was 75 %.

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Cu(In,Ga)$Se_2$ Absorber Layer Prepared by Electron Beam Evaporation Method for Thin Film Solar Cell

  • Li, Zhao-Hui;Cho, Eou-Sik;Noh, Gap-Seong;Lim, Jae-Eok;Pahk, Heui-Jae;Bae, Kyung-Bin;Kwon, Sang-Jik
    • 한국정보디스플레이학회:학술대회논문집
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    • 2009.10a
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    • pp.1564-1567
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    • 2009
  • Cu(In,Ga)$Se_2$ (CIGS) thin films were formed using CIGS bulk by electron-beam evaporation method with an evaporation current from 20 mA to 90 mA. The experimental results showed that the chemical compositions and the properties of CIGS films varied with the different evaporation current. The Cu-rich CIGS film was deposited successfully with a band gap of 1.20 eV when the evaporation current was 90 mA.

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Laser Direct Etching on Transparent Conductive Oxide Films Sputtered on Polycarbonate Substrates (PC 기판상에 스퍼터링된 투명전도 산화막의 레이저 식각 특성)

  • Lee, Jeongmin;Kwon, Sang Jik;Cho, Eou Sik
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.27 no.3
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    • pp.146-150
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    • 2014
  • As a method of simple patterning of transparent conductive oxide (TCO) films deposited on flexible substrates, laser direct etching was carried out on TCO films sputtered on polycarbonate (PC) substrates. As a result of different binding energies in TCO films, indium tin oxide (ITO) and indium gallium zinc oxide (IGZO) were more easily etched than zinc oxide with different $Nd:YVO_4$ laser beam conditions.

A Study on the Effects of the Optical Characteristics of Backlight Sources on the Photo Leakage Currents of a-Si:H Thin Film Transistor (비정질 실리콘 TFT의 광누설 전류에 Backlight 광원의 광학적 특성이 미치는 영향에 대한 연구)

  • Im, Seung-Hyeok;Kwon, Sang-Jik;Cho, Eou-Sik
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.21 no.9
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    • pp.844-847
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    • 2008
  • The photo leakage currents of a conventional hydrogenated amorphous silicon(a-Si:H) thin film transistor(TFT) were investigated and analyzed in case of illumination from various light sources such as halogen lamp, cold cathode fluorescent lamp(CCFL) backlight, and white light emitting diode(LED) backlight. The photo leakage characteristics showed the apparent differences in the leakage level and in the $I_{on}/I_{off}$ ratio in spite of the similar luminances of light sources. This leakage level is expected to be related to the wavelength of the lowest intensity peak from the spectral characteristics of light sources.