AlN overgrowth of nano-pillar-patterned sapphire with different offcut angle by metalorganic vapor phase epitaxy

S. Walde, S. Hagedorn, P.-M. Coulon, A. Mogilatenko, C. Netzel, J. Weinrich, N. Susilo, E. Ziffer, L. Matiwe, C. Hartmann, G. Kusch, A. Alasmari, G. Naresh-Kumar, C. Trager-Cowan, T. Wernicke, T. Straubinger, M. Bickermann, R. W. Martin, P. A. Shields, M. KneisslM. Weyers

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

We present overgrowth of nano-patterned sapphire with different offcut angles by metalorganic vapor phase epitaxy. Hexagonal arrays of nano-pillars were prepared via Displacement Talbot Lithography and dry-etching. 6.6 µm crack-free and fully coalesced AlN was grown on such substrates. Extended defect analysis comparing X-ray diffraction, electron channeling contrast imaging and selective defect etching revealed a threading dislocation density of about 109 cm-2. However, for c-plane sapphire offcut of 0.2° towards m direction the AlN surface shows step bunches with a height of 10 nm. The detrimental impact of these step bunches on subsequently grown AlGaN multi-quantum-wells is investigated by cathodoluminescence and transmission electron microscopy. By reducing the sapphire offcut to 0.1° the formation of step bunches is successfully suppressed. On top of such a sample an AlGaN-based UVC LED heterostructure is realized emitting at 265 nm and showing an emission power of 0.81 mW at 20 mA (corresponds to an external quantum efficiency of 0.86 %).
Original languageEnglish
Article number125343
Number of pages6
JournalJournal of Crystal Growth
Volume531
Early online date13 Nov 2019
DOIs
Publication statusPublished - 1 Feb 2020

Keywords

  • metal organic vapor phase epitaxy
  • nitrides
  • sapphire
  • light emitting diodes

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    Data for: "AlN overgrowth of nano-pillar-patterned sapphire with different offcut angle by metalorganic vapor phase epitaxy"

    Walde, S. (Creator), Hagedorn, S. (Creator), Coulon, P. (Creator), Mogilatenko, A. (Contributor), Netzel, C. (Contributor), Weinrich, J. (Contributor), Susilo, N. (Contributor), Ziffer, E. (Contributor), Matiwe, L. (Contributor), Hartmann, C. (Contributor), Kusch, G. (Creator), Alasmari, A. M. A. (Creator), Gunasekar, N. (Contributor), Trager-Cowan, C. (Creator), Wernicke, T. (Contributor), Straubinger, T. (Contributor), Bickermann, M. (Contributor), Martin, R. (Contributor), Shields, P. A. (Contributor), Kneissl, M. (Contributor) & Weyers, M. (Contributor), University of Strathclyde, 25 Nov 2019

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    Equipment

    ESEM Quanta 250

    Robert Martin (Manager)

    Physics

    Facility/equipment: Equipment

  • Cite this

    Walde, S., Hagedorn, S., Coulon, P-M., Mogilatenko, A., Netzel, C., Weinrich, J., Susilo, N., Ziffer, E., Matiwe, L., Hartmann, C., Kusch, G., Alasmari, A., Naresh-Kumar, G., Trager-Cowan, C., Wernicke, T., Straubinger, T., Bickermann, M., Martin, R. W., Shields, P. A., ... Weyers, M. (2020). AlN overgrowth of nano-pillar-patterned sapphire with different offcut angle by metalorganic vapor phase epitaxy. Journal of Crystal Growth, 531, [125343]. https://doi.org/10.1016/j.jcrysgro.2019.125343