• Title/Summary/Keyword: Illumination Fall-off

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Electrical and Optical Switching Characteristics of Gold-Doped P-I-N Diodes (금이 도우핑된 P-I-N 다이오드의 전기적 및 광학적 스위칭 특성)

  • Min, Nam-Ki;Ha, Dong-Sik;Lee, Seong-Jae
    • Proceedings of the KIEE Conference
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    • 1996.07c
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    • pp.1547-1549
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    • 1996
  • The electrical and optical switching characteristics of gold-doped silicon p-i-n diodes have been investigated. The device shows a dark switching voltage of about 500 V. The switching voltage decreases rapidly when the illumination level is increased. The differential sensitivity of optical gating over linear region is $d(V_{Th}/V_{Tho})/dP_{Ph}$=0.25/uW. The turn-on delay time and the turn-on rise time decrease with increasing optical pulse power. The turn-off delay and the fall time are negligible.

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Fabrication and performance evaluation of ultraviolet photodetector based on organic /inorganic heterojunction

  • Abdel-Khalek, H.;El-Samahi, M.I.;Salam, Mohamed Abd-El;El-Mahalawy, Ahmed M.
    • Current Applied Physics
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    • v.18 no.12
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    • pp.1496-1506
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    • 2018
  • Organic/inorganic ultraviolet photodetector was fabricated using thermal evaporation technique. Organic/inorganic heterojunction based on thermally evaporated copper (II) acetylacetonate thin film of thickness 200 nm deposited on an n-type silicon substrate is introduced. I-V characteristics of the fabricated heterojunction were investigated under UV illumination of intensity $65mW/cm^2$. The diode parameters such as ideality factor, n, barrier height, ${\Phi}_B$, and reverse saturation current, $I_s$, were determined using thermionic emission theory. The series resistance of the fabricated diode was determined using modified Nord's method. The estimated values of series resistance and barrier height of the diode were about $0.33K{\Omega}$ and 0.72 eV, respectively. The fabricated photodetector exhibited a responsivity and specific detectivity about 9 mA/W and $4.6{\times}10^9$ Jones, respectively. The response behavior of the fabricated photodetector was analyzed through ON-OFF switching behavior. The estimated values of rise and fall time of the present architecture under UV illumination were about 199 ms and 154 ms, respectively. Finally, enhancing the photoresponsivity of the fabricated photodetector, post-deposition plasma treatment process was employed. A remarkable modification of the device performance was noticed as a result of plasma treatment. These modifications are representative in a decrease of series resistance and an increase of photoresponsivity and specific detectivity. The process of plasma treatment achieved an increment of external quantum efficiency from 5.53% to 8.34% at -3.5 V under UV illumination.

Radiometric Correction Algorithm for KITSAT-3 Images (우리별 3호 영상의 복사학적 보정 알고리즘)

  • Shin, Dongseok;Kwak, Sunghee;Kim, Tag-Gon
    • Journal of the Korean Association of Geographic Information Studies
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    • v.2 no.2
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    • pp.9-14
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    • 1999
  • This paper describes an algorithm for the correction of major radiometric errors shown in MEIS (Multi-spectral Earth Imaging System) images on board KITSAT-3. MEIS images contain various radiometric errors as also shown in the images obtained from other remote sensing sensors. This paper introduces the two major radiometric error sources shown in MEIS images and the corresponding correction algorithm. The proposed algorithm was integrated to an operational preprocessing software and validated by applying the algorithm to several tens of MEIS images. This algorithm will therefore applied operationally to raw MEIS images before they are distributed to users.

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