Fabrication of p-type ZnO nanorods/n-GaN film heterojunction ultraviolet light-emitting diodes by aqueous solution method

Authors

  • Nguyen Xuan Sang,

    1. Singapore MIT Alliance, E4-04-10, 4 Engineering Drive 3, 117576 Singapore, Singapore
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  • Tay Chuan Beng,

    1. NUSNNI-Nanocore Laboratory, E3-05-29, Faculty of Engineering, National University of Singapore, 2 Engineering Drive 3, 117581 Singapore, Singapore
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  • Tang Jie,

    1. NUSNNI-Nanocore Laboratory, E3-05-29, Faculty of Engineering, National University of Singapore, 2 Engineering Drive 3, 117581 Singapore, Singapore
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  • Eugene A. Fitzgerald,

    1. Singapore MIT Alliance, E4-04-10, 4 Engineering Drive 3, 117576 Singapore, Singapore
    2. Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139-4307, USA
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  • Chua Soo Jin

    Corresponding author
    1. NUSNNI-Nanocore Laboratory, E3-05-29, Faculty of Engineering, National University of Singapore, 2 Engineering Drive 3, 117581 Singapore, Singapore
    2. Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research, 3 Research Link, 117602 Singapore, Singapore
    • Singapore MIT Alliance, E4-04-10, 4 Engineering Drive 3, 117576 Singapore, Singapore
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Abstract

Zinc oxide (ZnO) is a wide-bandgap material with excellent optical properties for optoelectronics applications. ZnO nanostructures are attractive for research because it is easy to fabricate in single-crystalline form and it has interesting physical properties at the nanoscale. In this paper, we report our successful growth of a p-type ZnO nanorods/n-GaN film heterojunction ultraviolet light-emitting diode (LED). The heterojunction LED shows its advantages over a p-ZnO film/n-GaN film heterojunction. The LED demonstrates a rectifying IV characteristics with a turn-on voltage of 2.7 V. The ideality factor is 6.5. The existences of interface charges in the interface are the reason for this low turn-on voltage and high ideality factor in the heterojunction. Electroluminescence (EL) spectra of the LED consist of an ultraviolet peak at 378 nm and a broad yellow emission centered at 560 nm. Fitting and comparing EL of the LED with PL of p-ZnO and n-GaN show that p-ZnO contributes more to the EL than n-GaN.

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