Berlin 2012 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
HL: Fachverband Halbleiterphysik
HL 24: Poster Session: Ge/Si/SiC / III - V Semiconductors
HL 24.22: Poster
Montag, 26. März 2012, 16:00–19:00, Poster D
Photoluminescence spectra of SiGe quantum islands grown on prepatterned Si substrates: evidence of carrier interaction and biexcitonic transitions — •Petr Klenovský1,2, Moritz Brehm3, Vlastimil Křápek1,4, Elisabeth Lausecker3, Florian Hackl3, Thomas Fromherz3, Günther Bauer3, and Josef Humlíček3 — 1Department of Condensed Matter Physics, Faculty of Science, Masaryk University, Kotlářská 2, 61137 Brno, Czech Republic — 2CEITEC - Central European Institute of Technology, Masaryk University, Kamenice 753/5, 62500 Brno, Czech Republic — 3Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, 4040 Linz, Austria — 4Institute of Physics, Academy of Sciences of the Czech republic, Cukrovarnická 10, Praha 6, 162 53, Czech Republic
The pumping intensity (I) dependence of the photoluminescence (PL) spectra of SiGe quantum dots grown on prepatterned Si(001) substrates was studied. Their analysis revealed up to seven spectral bands attributed to phonon-assisted recombinations, no-phonon recombinations of the ground and excited states of excitons, all showing linear dependencies of the peak intensity on I. At large values of I, additional lines with a quadratic dependence on I appear in he PL spectra that are assigned to biexciton transitions. The experimentally obtained energies of the no-phonon transitions are in good agreement with the exciton and biexciton energies calculated within the framework of a k→·p→ theory. To the best of our knowledge this is the first clear evidence of the carrier interaction and biexcitonic transitions in SiGe/Si QDs.