Self-organized formation of GaSb/GaAs quantum rings.
Ring-shaped GaSb/GaAs quantum dots, grown by molecular beam epitaxy, were studied using cross-sectional scanning tunneling microscopy. These quantum rings have an outer shape of a truncated pyramid with baselengths around 15 nm and heights of about 2 nm but are characterized by a clear central opening extending over about 40% of the outer baselength. They form spontaneously during the growth and subsequent continuous capping of GaSb/GaAs quantum dots due to the large strain and substantial As-for-Sb exchange reactions leading to strong Sb segregation.
Timm
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Institut für Festkörperphysik, Technische Universität Berlin, 10623 Berlin, Germany. timm@physik.tu-berlin.de
Eisele
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Lenz
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Ivanova
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Balakrishnan
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Huffaker
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Dähne
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