Voltage-controlled anodic oxidation of porous fluorescent sic for effective surface passivation

Kosuke Yanai, Weifang Lu*, Yoma Yamane, Dong Pyo Han, Haiyan Ou, Motoaki Iwaya, Tetsuya Takeuchi, Satoshi Kamiyama, Isamu Akasaki

*Corresponding author for this work

    Research output: Contribution to journalJournal articleResearchpeer-review

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    Abstract

    This study investigated the fabrication of porous fluorescent SiC using a constant voltage-controlled anodic oxidation process. The application of a high, constant voltage resulted in a spatial distinction between the porous structures formed inside the fluorescent SiC substrates, due to the different etching rates at the terrace and the large step bunches. Large, dendritic porous structures were formed as the etching process continued and the porous layer thickened. Under the conditions of low hydrofluoric acid (HF) concentration, the uniformity of the dendritic porous structures through the entire porous layer was considerably improved compared with the conditions of high HF concentration. The resulting large uniform structure offered a sizable surface area, and promoted the penetration of atomic layer-deposited (ALD) Al2 O3 films (ALD–Al2 O3 ). The emission intensity in the porous fluorescent SiC was confirmed via photoluminescence (PL) measurements to be significantly improved by a factor of 128 after ALD passivation. With surface passivation, there was a clear blueshift in the emission wavelength, owing to the effective suppression of the non-radiative recombination rate in the porous structures. Furthermore, the spatial uniformity of emitted light was examined via PL mapping using three different excitation lasers, which resulted in the observation of uniform and distinctive emissions in the fluorescent SiC bulk and porous areas.

    Original languageEnglish
    Article number2075
    JournalNanomaterials
    Volume10
    Issue number10
    Number of pages10
    ISSN2079-4991
    DOIs
    Publication statusPublished - Oct 2020

    Keywords

    • Anodic oxidation
    • Fluorescent SiC
    • Photoluminescence
    • Porous structures
    • Surface passivation

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