Dresden 2003 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 44: Quantenpunkte und -dr
ähte: Optische Eigenschaften III
HL 44.4: Vortrag
Donnerstag, 27. März 2003, 15:15–15:30, BEY/118
Optical characterization of single self-assembled InAs/InGaAlAs quantum dashes — •Tobias Mensing, Lukas Worschech, Yutien Ling, Stefan Kaiser, Ruth Schwertberger, Johann Peter Reithmaier, and Alfred Forchel — Technische Physik, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
Optical spectroscopy of single self-assembled semiconductor quantum dots is a very active field to study physical properties of three dimensionally confined exciton systems. Up to now most quantum dot systems emit at wavelengths below 1 µm. Here we present optical studies of elongated InAs quantum dots further referred to as InAs quantum dashes emitting in the telecommunication wavelength ranges of 1.3 and 1.5 µm. Small mesa structures with only a few self-assembled InAs dashes for optical studies were realized by electron beam lithography and etching techniques. The heterostructure was grown by molecular beam epitaxy lattice matched to an InP substrate and consists of an In0.53Ga0.23Al0.24As layer embedding in the center 3.3 monolayers of InAs. By self assembly InAs dashes were formed. At low temperatures narrow emission lines associated with electron-hole pairs confined in single dashes are observed. Biexciton transitions with typical binding energies of about 3.5 meV are found. The diamagnetic shift and the Zeeman splitting of single excitons are studied in magnetic fields up to 8 T in Faraday configuration. A large variation of the exciton g factor with the emission energy of quantum dashes is observed.