Growth, structural and optical properties of GaN/AlN and GaN/GaInN nanowire heterostructures
| Autor: | Cédric Leclere, D. Camacho, Bruno Gayral, Ana Cros, Karine Hestroffer, G. Tourbot, Hubert Renevier, Bruno Daudin, Catherine Bougerol, Yann-Michel Niquet, Diane Sam-Giao, Rafael Mata |
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| Rok vydání: | 2012 |
| Předmět: |
Materials science
Photoluminescence business.industry Relaxation (NMR) Nucleation Nanowire Shell (structure) Heterojunction Physics and Astronomy(all) Xrays diffraction symbols.namesake nanowires molecular beam epitaxy Raman spectroscopy symbols III nitride wide gap semiconductors Optoelectronics photoluminescence business high resolution electron microscopy Molecular beam epitaxy |
| Zdroj: | Physics Procedia. 28:5-16 |
| ISSN: | 1875-3892 |
| DOI: | 10.1016/j.phpro.2012.03.662 |
| Popis: | After discussing the GaN NW nucleation issue, we will present the structural properties of axial and radial (i.e. core/shell) GaN/AlN NW heterostructures and adress the issue of critical thickness during the growth of such heterostructures. Next, we will present the growth of InGaN NWs on a GaN NW base. It will be shown that the morphology and structural properties of the InGaN NW sections depend on the In content: for high In content a flat top is observed and plastic relaxation is occuring, with mismatch dislocations formed at the InGaN/GaN interface. By contrast, for In content below 25% InGaN NWs exhibit a pencil-like shape assigned to a purely elastic strain relaxation process, without formation of dislocations. Such a strain relaxation process was found to be associated with the spontaneous formation of an InGaN/GaN core-shell heterostructure. As concerns optical properties, it will be shown that the purely elastic relaxation process is associated with a marked In clustering. As a consequence, for samples with a 17% nominal In content, data were found to exhibit a S-shape characteristic of localization, with a minimum around 110K. By contrast, for a 40% In content PL data suggest that localization is much weaker. Finally, a growth model of InGaN/GaN heterostructures will be proposed. |
| Databáze: | OpenAIRE |
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