Spontaneous nucleation and growth of GaN nanowires: Fundamental role of crystal polarity
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| Main Authors: | , , , , , , |
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| Format: | Preprint |
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2024
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| _version_ | 1866909092590649344 |
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| author | Fernández-Garrido, Sergio Kong, Xiang Gotschke, Tobias Calarco, Raffaella Geelhaar, Lutz Trampert, Achim Brandt, Oliver |
| author_facet | Fernández-Garrido, Sergio Kong, Xiang Gotschke, Tobias Calarco, Raffaella Geelhaar, Lutz Trampert, Achim Brandt, Oliver |
| contents | We experimentally investigate whether crystal polarity affects the growth of GaN nanowires in plasma-assisted molecular beam epitaxy and whether their formation has to be induced by defects. For this purpose, we prepare smooth and coherently strained AlN layers on 6H-SiC(0001) and SiC(000$\bar{1}$) substrates to ensure a well-defined polarity and an absence of structural and morphological defects. On N-polar AlN, a homogeneous and dense N-polar GaN nanowire array forms, evidencing that GaN nanowires form spontaneously in the absence of defects. On Al-polar AlN, we do not observe the formation of Ga-polar GaN NWs. Instead, sparse N-polar GaN nanowires grow embedded in a Ga-polar GaN layer. These N-polar GaN nanowires are shown to be accidental in that the necessary polarity inversion is induced by the formation of Si$_{x}$N. The present findings thus demonstrate that spontaneously formed GaN nanowires are irrevocably N-polar. Due to the strong impact of the polarity on the properties of GaN-based devices, these results are not only essential to understand the spontaneous formation of GaN nanowires but also of high technological relevance. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2402_01755 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Spontaneous nucleation and growth of GaN nanowires: Fundamental role of crystal polarity Fernández-Garrido, Sergio Kong, Xiang Gotschke, Tobias Calarco, Raffaella Geelhaar, Lutz Trampert, Achim Brandt, Oliver Materials Science We experimentally investigate whether crystal polarity affects the growth of GaN nanowires in plasma-assisted molecular beam epitaxy and whether their formation has to be induced by defects. For this purpose, we prepare smooth and coherently strained AlN layers on 6H-SiC(0001) and SiC(000$\bar{1}$) substrates to ensure a well-defined polarity and an absence of structural and morphological defects. On N-polar AlN, a homogeneous and dense N-polar GaN nanowire array forms, evidencing that GaN nanowires form spontaneously in the absence of defects. On Al-polar AlN, we do not observe the formation of Ga-polar GaN NWs. Instead, sparse N-polar GaN nanowires grow embedded in a Ga-polar GaN layer. These N-polar GaN nanowires are shown to be accidental in that the necessary polarity inversion is induced by the formation of Si$_{x}$N. The present findings thus demonstrate that spontaneously formed GaN nanowires are irrevocably N-polar. Due to the strong impact of the polarity on the properties of GaN-based devices, these results are not only essential to understand the spontaneous formation of GaN nanowires but also of high technological relevance. |
| title | Spontaneous nucleation and growth of GaN nanowires: Fundamental role of crystal polarity |
| topic | Materials Science |
| url | https://arxiv.org/abs/2402.01755 |