Dresden 2014 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 78: Quantum dots: Preparation and characterization

HL 78.7: Vortrag

Mittwoch, 2. April 2014, 18:00–18:15, POT 251

Growth, structure and spectroscopy of In0.50Ga0.50As quantum dots grown by MOVPE on GaP(001) — •Elisa Maddalena Sala, Gernot Stracke, Manuel Gschrey, Christopher Prohl, Andrei Schliwa, Holger Eisele, André Strittmatter, and Dieter Bimberg — Institut für Festkörperphysik, Technische Universität Berlin Hardenbergstr. 36 10623 Berlin, Germany

InGaAs quantum dots (QDs) on GaP have recently attracted great attention for application in nano memory cells and monolithic III/V on silicon photonics. In0.50Ga0.50As QDs on GaP(001) grown by metalorganic vapor phase epitaxy exhibit truncated inverted pyramidal shape and strong indium agglomeration at QD tops. For injection of electrons into the QDs, indirect bandgap of GaP with lowest conduction band states at the X-point has to be taken into account. 8-band k·p theory predicts a QD size- and strain- dependent transition from indirect to direct optical emission. By preparing QD ensemble of ultra-low density, detection of luminescence from individual InGaAs/GaP QDs is enabled for the first time. Narrow emission lines with FWHM of 52 µmeV showing no spectral jitter suggest that no electrical active defects are present in the QD vicinity. Temperature-dependent cathodoluminescence investigations allow to study the electronic structure of InGaAs/GaP QDs since thermally induced strain alters the electronic structure of the QDs allowing to research for the transition from indirect-to-direct optical emission.
Towards QD positioning, initial studies on buried stressor formation by selective lateral oxidation of thin AlP layers will be presented.

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