• 제목/요약/키워드: device physics

검색결과 719건 처리시간 0.046초

Electroluminescence of a red fluorescent dye doped in an $Alq_{3}$:rubrene Mixed Host

  • Kang, Hee-Young;kang, Gi-Wook;Lee, Chang-Hee
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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    • pp.948-951
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    • 2003
  • The electroluminescence (EL) properties were studied in organic light-emitting diodes with a red fluorescent dye, 4- (dicyanomethylene)- 2- tert-butyl-6 (1,1,7,7-tetramethyljulolidyl-9-enyl)- 4H- pyran (DCJTB) doped into tris-(8-hydroxyquinoline)aluminum ($Alq_{3}$), rubrene and the mixed matrix of $Alq_3$ and rubrene. The device with DCJTB doped into the $Alq_{3}$:rubrene mixed host shows an efficient red emission from DCJTB with a negligible EL emission from $Alq_{3}$ and a lower EL onset voltage compared to the device with DCJTB doped into the $Alq_{3}$ only host. The quantum efficiency is almost temperature-independent for the device with the $Alq_3:rubrene$ mixed host. The results indicate that recombination of injected electrons and holes occurs on rubrene and subsequent energy transfer to DCJTB dominates in the device with the $Alq_{3}$:rubrene mixed host.

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Design of compact klystron amplifier using Field-emitter-arrays (FEA)-based cathode

  • Jin, Jeong-Gu;Ha, Hyun-Jun;Park, Gun-Sik
    • Journal of Korean Vacuum Science & Technology
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    • 제3권1호
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    • pp.59-65
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    • 1999
  • There has been an interest to develop an efficient, compact microwave device using field-emitter-arrays (FEA)-based cathode. Toe valuate the optimum device-efficiency in a compact size, the propagation properties of the premodulated electron beam for the FEA-based cathode is studied in detail by the computer simulation using a PIC code, MAGIC. For the premodulated electron beam whose phase of the energy leads the phase of the current by $\pi$/2, the amplitude of the downstream current modulation can be kept as high as the initial modulation level. Using the beam parameters with the beam voltage of 6kV and the current of 2.0A, 30% of efficiency is predicted when the quality factor of 800 is chosen. the device length is reduced about twice compared with that of the conventional device. The design of practical planar cathode is carried out to meet the minimum diameter of the electron beam as 0.5 mm.

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Coulomb Interaction Induced Gap in an Al/SiO2/Si:P tunnelling Device

  • Jo, Yongcheol;Kim, Jongmin;Cho, Sangeun;Kim, Hyungsang;Im, Hyunsik
    • Applied Science and Convergence Technology
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    • 제26권3호
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    • pp.50-51
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    • 2017
  • Strongly correlated electron systems which induce strong electron-electron interaction at ultra-low temperatures have always been an intriguing topic in mesoscopic condensed matter physics. Below 130 mK, a peculiar gap can be found in Al/$SiO_2$/Si:P structured tunnelling devices. The gap survives at the base temperature of more than 1800 gauss (30 mK), contrary to the superconductivity of the top Al electrode, which is completely suppressed above 100 gauss. This outcome implies that the observed gap is induced by Coulomb interaction in the heavily doped Si.

Pixel isolated liquid crystal mode for flexible displays

  • Lee, Hyun-Gi;Jung, Jong-Wook;Kim, Jae-Hoon
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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    • pp.615-618
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    • 2003
  • We developed a new device structure using anisotropic phase sepraration from liquid crystals (LCs) and polymer composite materials for flexible display applications. In the device, the LC molecules are isolated in pixels where LCs are surrounded by polymer layers. These devices show very good mechanical stability against external pressure. The electro-optic characteristics and the mechanical stability of the devices are discussed in view of the flexible display applications.

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Chiral liquid crystals in photonic device applications

  • Gleeson, Helen F.;Yoon, Hyung-Guen;Roberts, Nicholas W.
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
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    • pp.105-108
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    • 2007
  • Chiral liquid crystals exhibit band-gap structures responsive to electrical and optical fields, providing wide-ranging opportunities for photonics applications. We discuss three aspects of this technology: optics of chiral nematic devices and removal of pitch jumps; optical switching of chiral nematic materials; and using novel phases in photonic devices.

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