Anomalous nucleation of crystals within amorphous germanium nanowires during thermal annealing
Autor: | Jonathan A. Hinks, Osmane Camara, Anamul H. Mir, Graeme Greaves, Stephen E. Donnelly |
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Jazyk: | angličtina |
Rok vydání: | 2021 |
Předmět: |
Materials science
Annealing (metallurgy) Nanowire Nucleation chemistry.chemical_element Bioengineering Germanium 02 engineering and technology 010402 general chemistry 01 natural sciences law.invention law General Materials Science ddc:530 Electrical and Electronic Engineering Crystallization Mechanical Engineering General Chemistry 021001 nanoscience & nanotechnology 0104 chemical sciences Amorphous solid chemistry Chemical engineering Mechanics of Materials Transmission electron microscopy Crystallite 0210 nano-technology |
Zdroj: | Nanotechnology 32(28), 285707-(2021). doi:10.1088/1361-6528/abcef1 |
Popis: | In this work, germanium nanowires rendered fully amorphous via xenon ion irradiation have been annealed within a transmission electron microscope to induce crystallization. During annealing crystallites appeared in some nanowires whilst others remained fully amorphous. Remarkably, even when nucleation occurred, large sections of the nanowires remained amorphous even though the few crystallites embedded in the amorphous phase were formed at a minimum of 200 °C above the temperature for epitaxial growth and 100 °C above the temperature for random nucleation and growth in bulk germanium. Furthermore, the presence of crystallites was observed to depend on the diameter of the nanowire. Indeed, the formation of crystallites occurred at a higher annealing temperature in thin nanowires compared with thicker ones. Additionally, nanowires with a diameter above 55 nm were made entirely crystalline when the annealing was performed at the temperature normally required for crystallization in germanium (i.e. 500 °C). It is proposed that oxygen atoms hinder both the formation and the growth of crystallites. Furthermore, as crystallites must reach a minimum size to survive and grow within the amorphous nanowires, the instability of crystallites may also play a limited role for the thinnest nanowires. |
Databáze: | OpenAIRE |
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