| Autor: |
Schumann, O., Geelhaar, L., Riechert, H., Cerva, H., Abstreiter, G. |
| Předmět: |
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| Zdroj: |
Journal of Applied Physics; 9/1/2004, Vol. 96 Issue 5, p2832-2840, 9p, 4 Black and White Photographs, 1 Diagram, 4 Graphs |
| Abstrakt: |
InAs(N) quantum dots (QDs) were grown on GaAs(001) by solid source molecular beam epitaxy. Nitrogen was supplied by a radio-frequency plasma cell. The samples were characterized by atomic force microscopy, photoluminescence (PL) spectroscopy, and transmission electron microscopy. With an increasing amount of nitrogen supplied to the surface, large QDs form and the small QDs typical for nitrogen free growth gradually disappear. For intermediate amounts of nitrogen, small and large QDs coexist in a bimodal distribution. The large QDs contain misfit dislocations and are thus plastically relaxed. These dislocations are already induced in the wetting layer by exposure to the nitrogen plasma and act as nucleation centers for the large QDs. The incorporation of material into relaxed QDs is preferred, which leads to an elimination of the small strained QDs. When increasing the amount of nitrogen, the expected strong redshift in the PL wavelength does not occur. This leads to the conclusion that only a little nitrogen is incorporated into the small coherent QDs. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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