Wurtzite-to Amorphous-to Cubic Phase Transition of GaN1-XAsx Alloys with Increasing as Content
| Autor: | A. X. Levander, Sergei V. Novikov, Kin Man Yu, Wladek Walukiewicz, Zuzanna Liliental-Weber, C. T. Foxon, R. dos Reis |
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| Rok vydání: | 2012 |
| Předmět: |
Materials science
Amorphous metal Annealing (metallurgy) Band gap Alloy Analytical chemistry engineering.material Condensed Matter Physics Atomic and Molecular Physics and Optics Amorphous solid Crystallography Transmission electron microscopy engineering General Materials Science Wurtzite crystal structure Molecular beam epitaxy |
| Zdroj: | Solid State Phenomena. 186:74-77 |
| ISSN: | 1662-9779 |
| DOI: | 10.4028/www.scientific.net/ssp.186.74 |
| Popis: | This paper describes Transmission Electron Microscopy studies of the structural changes of GaN1-xAsx alloys grown by Molecular Beam Epitaxy at low temperatures on Al2O3 substrate. We found that by lowering the growth temperature increasing amount of As can be incorporated in GaN1-xAsx forming a single phase alloy. For the low As content a columnar growth of wurtzite structure is observed but for increasing As in the range of 0.170.75 the layer becomes amorphous. Increase in Ga flux at low growth temperature (about 200°C) leads to columnar alloys with As content >75% with a cubic structure. In addition to the structural changes monotonic change of the band gap is also observed with the As content in the alloy. The amorphous alloy is stable up to annealing at temperatures not higher than 600°C. Annealing at higher temperature leads to phase separation of GaAs:N and GaN:As confirmed by Z-contrast electron microscopy. |
| Databáze: | OpenAIRE |
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