Magnetoexcitons in Type-II Self-Assembled Quantum Dots and Quantum-Dot Superlattices |
| Journal |
Materials Science Forum (Volume 518) |
| Volume |
Recent Developments in Advanced Materials and Processes |
| Edited by |
Dragan P. Uskokovic, Slobodan K. Milonjic and Dejan I. Rakovic |
| Pages |
51-56 |
| DOI |
10.4028/www.scientific.net/MSF.518.51 |
| Online since |
July, 2006 |
| Authors |
Dj. Veljković,
M. Tadić,
F.M. Peeters
|
| Keywords |
Exciton, Quantum Dots (QDs), Self-Assembled |
| Abstract |
Exciton states in type-II InP/InGaP and GaSb/GaAs self-assembled quantum dots and
quantum-dot superlattices subject to a normal magnetic field are calculated. Strain is explicitly
taken into account in single particle models of the electronic structure, while an exact
diagonalization approach is adopted to compute the exciton states. Strain reverts type II band
alignment in InP quantum dots to type I, therefore no transitions between the lowest energy states of
different angular momenta are observed. On the other hand, strain increases the barrier for the
electron in the conduction band of GaSb/GaAs quantum dots, therefore the exciton, being
composed of electron and hole states of various angular momenta, may have a finite angular
momentum in the ground state. Consequently, the oscillator strength in the InP single quantum dot
and quantum-dot superlattice increases with the magnetic field, while the angular momentum
transitions between the bright and the dark exciton states in the GaSb system bring about decay of
the oscillator strength when the magnetic field exceeds a certain value. |
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