InGaN photodiodes using CaF2 insulator for high-temperature UV detection

Authors

  • L. W. Sang,

    Corresponding author
    1. Optical and Electronic Materials Unit, National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
    • Optical and Electronic Materials Unit, National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
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  • M. Y. Liao,

    1. Optical and Electronic Materials Unit, National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
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  • Y. Koide,

    1. Optical and Electronic Materials Unit, National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
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  • M. Sumiya

    1. Optical and Electronic Materials Unit, National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
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Abstract

The authors report on a thermally-stable ultraviolet-A photodiode using CaF2 as the insulation layer in the metal-insulator-semiconductor (MIS) structure based on a high-quality InGaN film. Compared to the Schottky photodiode (SPD) without the insulator, the MIS-SPD device maintains a low reverse leakage current, a high photo-to-dark current ratio and fast response at the temperature as high as 523 K, indicating CaF2 as a good candidate for the III-Nitride devices. The overall photoresponse properties of the MIS-SPD are governed by the metal/insulator/semiconductor interfaces. The photocurrent gain at reverse biases from room-temperature to 463 K is interpreted in term of thermionic-field emission (TFE) and field emission mechanism, while TFE becomes the dominant mechanism at higher temperatures (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

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