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GaAs structures with InAs and As quantum dots produced in a single molecular beam epitaxy process
- Source :
- Semiconductors. 43:1617-1621
- Publication Year :
- 2009
- Publisher :
- Pleiades Publishing Ltd, 2009.
-
Abstract
- Epitaxial GaAs layers containing InAs semiconductor quantum dots and As metal quantum dots are grown by molecular beam epitaxy. The InAs quantum dots are formed by the Stranskii-Krastanow mechanism, whereas the As quantum dots are self-assembled in the GaAs layer grown at low temperature with a large As excess. The microstructure of the samples is studied by transmission electron microscopy. It is established that the As metal quantum dots formed in the immediate vicinity of the InAs semiconductor quantum dots are larger in size than the As quantum dots formed far from the InAs quantum dots. This is apparently due to the effect of strain fields of the InAs quantum dots upon the self-assembling of As quantum dots. Another phenomenon apparently associated with local strains around the InAs quantum dots is the formation of V-like defects (stacking faults) during the overgrowth of the InAs quantum dots with the GaAs layer by low-temperature molecular beam epitaxy. Such defects have a profound effect on the self-assembling of As quantum dots. Specifically, on high-temperature annealing needed for the formation of large-sized As quantum dots by Ostwald ripening, the V-like defects bring about the dissolution of the As quantum dots in the vicinity of the defects. In this case, excess arsenic most probably diffuses towards the open surface of the sample via the channels of accelerated diffusion in the planes of stacking faults.
- Subjects :
- Ostwald ripening
Materials science
Nanostructure
Condensed matter physics
Condensed Matter::Other
Quantum point contact
Condensed Matter::Mesoscopic Systems and Quantum Hall Effect
Condensed Matter Physics
Epitaxy
Crystallographic defect
Atomic and Molecular Physics, and Optics
Semimetal
Electronic, Optical and Magnetic Materials
Condensed Matter::Materials Science
symbols.namesake
Quantum dot
symbols
Molecular beam epitaxy
Subjects
Details
- ISSN :
- 10906479 and 10637826
- Volume :
- 43
- Database :
- OpenAIRE
- Journal :
- Semiconductors
- Accession number :
- edsair.doi...........57fd78d28abdb3758bf772a1108435b3