GaSb/GaAs quantum dot formation and demolition studied with cross-sectional scanning tunneling microscopy
- Department of Applied Physics, Eindhoven University of Technology, Eindhoven 5612 AZ (Netherlands)
- Department of Physics, Lancaster University, Lancaster LA1 4YB (United Kingdom)
We present a cross-sectional scanning tunneling microscopy study of GaSb/GaAs quantum dots grown by molecular beam epitaxy. Various nanostructures are observed as a function of the growth parameters. During growth, relaxation of the high local strain fields of the nanostructures plays an important role in their formation. Pyramidal dots with a high Sb content are often accompanied by threading dislocations above them. GaSb ring formation is favored by the use of a thin GaAs first cap layer and a high growth temperature of the second cap layer. At these capping conditions, strain-driven Sb diffusion combined with As/Sb exchange and Sb segregation remove the center of a nanostructure, creating a ring. Clusters of GaSb without a well defined morphology also appear regularly, often with a highly inhomogeneous structure which is sometimes divided up in fragments.
- OSTI ID:
- 22025503
- Journal Information:
- Applied Physics Letters, Vol. 100, Issue 14; Other Information: (c) 2012 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
- Country of Publication:
- United States
- Language:
- English
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