Luminescence spectroscopy of InAs self-assembled quantum dots
β Scribed by P.D. Wang; J.L. Merz; G. Medeiros-Ribeiro; S. Fafard; P.M. Petroff; H. Akiyama; H. Sakaki
- Publisher
- Elsevier Science
- Year
- 1997
- Tongue
- English
- Weight
- 180 KB
- Volume
- 21
- Category
- Article
- ISSN
- 0749-6036
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β¦ Synopsis
We present selective photoluminescence and photoluminescence excitation spectroscopy on self-assembled quantum dots. These spectroscopic techniques reveal a large apparent 'Stokes' shift in In(Ga)As-Ga(Al)As self-assembled quantum dots. We demonstrate that the first two excited states observed in PLE originate from the doubly-degenerate first excited state. The ground state is not observed in the quantum dot PLE due to the sharp d-funtion-like density of states of individual dots. Our experimental data agree with a recent theoretical calculation, suggesting that both the degeneracy-lifting and broadening of energy levels are caused by the random potential of compositional, size and strain fluctuations. Due to large energy separations in these quantum dots, we also demonstrate the importance of multi-phonon relaxation processes.
π SIMILAR VOLUMES
A single-barrier GaAs/AlAs/GaAs heterostructure, with self-assembled In-based quantum dots incorporated in the AlAs tunnel barrier, exhibits a series of resonant peaks in the low temperature current-voltage characteristics. We argue that each peak arises from singleelectron tunneling through the dis
Molecular beam epitaxy has been used for growing self-assembled InAs quantum dots. A continuous variation of the InAs average coverage across the sample has been obtained by properly aligning the (001) GaAs substrate with respect to the molecular beam. Excitation of a large number of dots (laser spo