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, Gunnar Kusch, A. Alasmari, G. Naresh-kumar, C. Trager-cowan, T. Wernicke, T. Straubinger, M. Bickermann, Robert W. Martin, P.a. Shields, M. KneisslM. Weyers

Research output: Contribution to journalArticle

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
JournalJournal of Crystal Growth
Volume531
Early online date13 Nov 2019
DOIs
Publication statusPublished - 1 Feb 2020

Cite this

AlN overgrowth of nano-pillar-patterned sapphire with different offcut angle by metalorganic vapor phase epitaxy. / Walde, S.; Hagedorn, S.; Coulon, P.-m.; Mogilatenko, A.; Netzel, C.; Weinrich, J.; Susilo, N.; Ziffer, E.; Matiwe, L.; Hartmann, C.; Kusch, Gunnar ; Alasmari, A.; Naresh-kumar, G.; Trager-cowan, C.; Wernicke, T.; Straubinger, T.; Bickermann, M.; Martin, Robert W.; Shields, P.a.; Kneissl, M.; Weyers, M.

In: Journal of Crystal Growth, Vol. 531, 125343, 01.02.2020.

Research output: Contribution to journalArticle

Walde, S, Hagedorn, S, Coulon, P, 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, RW, Shields, PA, Kneissl, M & Weyers, M 2020, 'AlN overgrowth of nano-pillar-patterned sapphire with different offcut angle by metalorganic vapor phase epitaxy', Journal of Crystal Growth, vol. 531, 125343. https://doi.org/10.1016/j.jcrysgro.2019.125343
Walde, S. ; Hagedorn, S. ; Coulon, P.-m. ; Mogilatenko, A. ; Netzel, C. ; Weinrich, J. ; Susilo, N. ; Ziffer, E. ; Matiwe, L. ; Hartmann, C. ; Kusch, Gunnar ; Alasmari, A. ; Naresh-kumar, G. ; Trager-cowan, C. ; Wernicke, T. ; Straubinger, T. ; Bickermann, M. ; Martin, Robert W. ; Shields, P.a. ; Kneissl, M. ; Weyers, M. / AlN overgrowth of nano-pillar-patterned sapphire with different offcut angle by metalorganic vapor phase epitaxy. In: Journal of Crystal Growth. 2020 ; Vol. 531.
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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{\%}).",
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T1 - AlN overgrowth of nano-pillar-patterned sapphire with different offcut angle by metalorganic vapor phase epitaxy

AU - Walde, S.

AU - Hagedorn, S.

AU - Coulon, P.-m.

AU - Mogilatenko, A.

AU - Netzel, C.

AU - Weinrich, J.

AU - Susilo, N.

AU - Ziffer, E.

AU - Matiwe, L.

AU - Hartmann, C.

AU - Kusch, Gunnar

AU - Alasmari, A.

AU - Naresh-kumar, G.

AU - Trager-cowan, C.

AU - Wernicke, T.

AU - Straubinger, T.

AU - Bickermann, M.

AU - Martin, Robert W.

AU - Shields, P.a.

AU - Kneissl, M.

AU - Weyers, M.

PY - 2020/2/1

Y1 - 2020/2/1

N2 - 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%).

AB - 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%).

U2 - 10.1016/j.jcrysgro.2019.125343

DO - 10.1016/j.jcrysgro.2019.125343

M3 - Article

VL - 531

JO - Journal of Crystal Growth

JF - Journal of Crystal Growth

SN - 0022-0248

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ER -