Molecular Beam Epitaxy of Al$\mathrm{_{1-x}}$Sc$\mathrm{_{x}}$N Nanowires: Towards Group-III Nitride Piezoelectric Nanogenerators with Enhanced Response

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Auteurs principaux: Notarangelo, Adriano, Songmuang, Rudeesun, Saleh, Mostafa, Buatip, Nattawadi, Florea, Ileana, Vennéguès, Philippe, Campbell, Aidan F., Tornatzky, Hans, Lähnemann, Jonas, Auzelle, Thomas, Geelhaar, Lutz, Brandt, Oliver, John, Philipp M.
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Publié: 2026
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author Notarangelo, Adriano
Songmuang, Rudeesun
Saleh, Mostafa
Buatip, Nattawadi
Florea, Ileana
Vennéguès, Philippe
Campbell, Aidan F.
Tornatzky, Hans
Lähnemann, Jonas
Auzelle, Thomas
Geelhaar, Lutz
Brandt, Oliver
John, Philipp M.
author_facet Notarangelo, Adriano
Songmuang, Rudeesun
Saleh, Mostafa
Buatip, Nattawadi
Florea, Ileana
Vennéguès, Philippe
Campbell, Aidan F.
Tornatzky, Hans
Lähnemann, Jonas
Auzelle, Thomas
Geelhaar, Lutz
Brandt, Oliver
John, Philipp M.
contents We study the molecular beam epitaxy of self-assembled Al$\mathrm{_{1-x}}$Sc$\mathrm{_{x}}$N nanowires on conductive TiN layers and demonstrate their application in piezoelectric nanogenerators. Wurtzite Al$\mathrm{_{1-x}}$Sc$\mathrm{_{x}}$N nanowires with uniform Sc incorporation are grown across a wide composition range (0<x<0.35). At substrate temperatures below 700 $^\circ{}$C, these nanowires exhibit an inversely tapered morphology, whereas higher temperatures favor the nucleation of additional branches due to a phase separation of Al$\mathrm{_{1-x}}$Sc$\mathrm{_{x}}$N into wurtzite AlN and rock-salt ScN. Phase-pure Al$\mathrm{_{1-x}}$Sc$\mathrm{_{x}}$N nanowires are integrated into vertical nanogenerators, where the metallic TiN substrate serves as bottom electrode. The fabricated polymer-nanowire composite devices achieve effective piezoelectric charge coefficients of up to 8.5 pC N$^{-1}$ at x=0.32, thus exceeding the piezoelectric response of bulk AlN by nearly a factor of two. Although the charge response remains lower compared to Al$\mathrm{_{1-x}}$Sc$\mathrm{_{x}}$N thin films, the reduced effective dielectric permittivity of the nanowire-polymer composites compensates the reduction in piezoelectric charge coefficient, eventually yielding a higher voltage response and comparable energy harvesting efficiency. Finally, effective medium modeling reveals that the device architecture is the primary factor limiting performance, providing general design principles for highly efficient nanowire-based piezoelectric energy harvesters.
format Preprint
id arxiv_https___arxiv_org_abs_2602_12956
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Molecular Beam Epitaxy of Al$\mathrm{_{1-x}}$Sc$\mathrm{_{x}}$N Nanowires: Towards Group-III Nitride Piezoelectric Nanogenerators with Enhanced Response
Notarangelo, Adriano
Songmuang, Rudeesun
Saleh, Mostafa
Buatip, Nattawadi
Florea, Ileana
Vennéguès, Philippe
Campbell, Aidan F.
Tornatzky, Hans
Lähnemann, Jonas
Auzelle, Thomas
Geelhaar, Lutz
Brandt, Oliver
John, Philipp M.
Materials Science
Mesoscale and Nanoscale Physics
Applied Physics
We study the molecular beam epitaxy of self-assembled Al$\mathrm{_{1-x}}$Sc$\mathrm{_{x}}$N nanowires on conductive TiN layers and demonstrate their application in piezoelectric nanogenerators. Wurtzite Al$\mathrm{_{1-x}}$Sc$\mathrm{_{x}}$N nanowires with uniform Sc incorporation are grown across a wide composition range (0<x<0.35). At substrate temperatures below 700 $^\circ{}$C, these nanowires exhibit an inversely tapered morphology, whereas higher temperatures favor the nucleation of additional branches due to a phase separation of Al$\mathrm{_{1-x}}$Sc$\mathrm{_{x}}$N into wurtzite AlN and rock-salt ScN. Phase-pure Al$\mathrm{_{1-x}}$Sc$\mathrm{_{x}}$N nanowires are integrated into vertical nanogenerators, where the metallic TiN substrate serves as bottom electrode. The fabricated polymer-nanowire composite devices achieve effective piezoelectric charge coefficients of up to 8.5 pC N$^{-1}$ at x=0.32, thus exceeding the piezoelectric response of bulk AlN by nearly a factor of two. Although the charge response remains lower compared to Al$\mathrm{_{1-x}}$Sc$\mathrm{_{x}}$N thin films, the reduced effective dielectric permittivity of the nanowire-polymer composites compensates the reduction in piezoelectric charge coefficient, eventually yielding a higher voltage response and comparable energy harvesting efficiency. Finally, effective medium modeling reveals that the device architecture is the primary factor limiting performance, providing general design principles for highly efficient nanowire-based piezoelectric energy harvesters.
title Molecular Beam Epitaxy of Al$\mathrm{_{1-x}}$Sc$\mathrm{_{x}}$N Nanowires: Towards Group-III Nitride Piezoelectric Nanogenerators with Enhanced Response
topic Materials Science
Mesoscale and Nanoscale Physics
Applied Physics
url https://arxiv.org/abs/2602.12956