Fabrication of transparent conducting polymer/GaN Schottky junction for deep level defect evaluation under light irradiation

Authors

  • Mickaël Lozac'h,

    1. Photonic Material Unit, National Institute for Materials Science, Tsukuba 305-0044, Japan
    2. Doctoral Program in Materials Science and Engineering, Tsukuba University, Tsukuba 305-8573, Japan
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  • Yoshitaka Nakano,

    1. Institute of Science and Technology Research, Chubu University, Kasugai, Aichi 487-8501, Japan
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  • Liwen Sang,

    1. ICYS-MANA, National Institute for Materials Science, Tsukuba 305-0044, Japan
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  • Kazuaki Sakoda,

    1. Photonic Material Unit, National Institute for Materials Science, Tsukuba 305-0044, Japan
    2. Doctoral Program in Materials Science and Engineering, Tsukuba University, Tsukuba 305-8573, Japan
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  • Masatomo Sumiya

    Corresponding author
    1. Wide Bandgap Materials Group, National Institute for Materials Science, Tsukuba 305-0044, Japan
    2. JST-ALCA, Japan Science and Technology Agency, Tokyo 102-0076, Japan
    • Phone: +81 29 860 4784, Fax: +81 29 851 4005
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Abstract

Transparent conducting polymer/n-GaN Schottky junction was fabricated in order to study deep level defects of III–V nitride films under light irradation. The leakage current was as low as 10−6 A cm−2 at reverse bias of 10 V. The Schottky barrier height reaches 1.15 eV under dark condition and under normalized solar spectrum AM1.5G the fill factor was up to 0.71 with an open-circuit voltage of 0.72 V and a short-circuit current of 0.37 mA cm−2. Deep level optical spectroscopy analysis revealed the presence of gallium vacancies (VGa) and/or related complexes impurities (VGa–ON and/or VGa–CN) at the interface between PEDOT:PSS and n-GaN. The Schottky and photovoltaic properties are discussed in term of deep level defects concentration.

original image

Schematic illustration of PEDOT:PSS/III–V nitride Schottky junction with a metallic front grid on PEDOT:PSS layer.

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