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Spacer layer thickness effects on the photoluminescence properties of InAs/GaAs quantum dot superlattices
- Source :
- physica status solidi (a), physica status solidi (a), Wiley, 2003, 199 (3), pp.457-463. ⟨10.1002/pssa.200306681⟩, physica status solidi (a), 2003, 199 (3), pp.457-463. ⟨10.1002/pssa.200306681⟩
- Publication Year :
- 2003
- Publisher :
- Wiley, 2003.
-
Abstract
- 68.37.Lp, 78.55.Cr, 78.67.Hc, 78.67.Pt, 79.40.+z InAs/GaAs vertically stacked self-assembled quantum dot (QD) structures with different GaAs spacer layer thicknesses are grown by solid source molecular beam epitaxy (SSMBE) and investigated by trans-mission electron microscopy (TEM) and photoluminescence (PL) spectroscopy. An increase in the polari-zation anisotropy is observed when the spacer layer thickness decreases. For a 10 monolayer (ML) thick inter-dots GaAs spacer, the TEM image shows an increase in the QD size when moving to the upper layer accompanied by the generation of dislocations. Consequently, the corresponding temperature-dependant PL properties are found to exhibit an unusual behaviour. The main PL peak is quenched at a temperature around 190 K giving rise to a broad background correlated with the formation of a miniband in the growth direction due to the strong interlayer coupling. For a thicker GaAs spacer layer (30 ML), multilayer QDs align vertically in stacks with no apparent structural defects. Over the whole temperature range, the exci-tonic band energies are governed by the Varshni empirical relation using InAs bulk parameters and the PL line width shows a slight monotonic increase. For a thinner GaAs interlayer, the thermal activation ener-gies of the carrier emission out of the quantum dots are found to be considerably small (about 25 meV) due to the existence of defects. By combining these structural and optical results, we can conclude that a thinner GaAs spacer has a poorer quality.
- Subjects :
- 010302 applied physics
Photoluminescence
Condensed matter physics
Chemistry
Superlattice
02 engineering and technology
Atmospheric temperature range
021001 nanoscience & nanotechnology
Condensed Matter Physics
01 natural sciences
Electronic, Optical and Magnetic Materials
Transmission electron microscopy
Quantum dot
0103 physical sciences
Monolayer
[SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics
Dislocation
0210 nano-technology
ComputingMilieux_MISCELLANEOUS
Molecular beam epitaxy
Subjects
Details
- ISSN :
- 1521396X, 00318965, and 18626319
- Volume :
- 199
- Database :
- OpenAIRE
- Journal :
- physica status solidi (a)
- Accession number :
- edsair.doi.dedup.....04cffe13ab6c00a79a14df36ae0b5341