Dresden 2009 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 42: Poster Session II (Nanostructures at surfaces: arrays; Nanostructures at surfaces: Dots, particles, clusters; Nanostructures at surfaces: Other; Nanostructures at surfaces: Wires, tubes; Metal substrates: Adsorption of O and/or H; Metal substrates: Clean surfaces; Metal substrates: Adsorption of organic/bio moledules; Metal substrates: Solid-liquid interfaces; Metal substrates: Adsorption of inorganic molecules; Metal substrates: Epitaxy and growth; Heterogeneous catalysis; Surface chemical reactions; Ab-initio approaches to excitations in condensed matter; Organic, polymeric, biomolecular films– also with adsorbates; Particles and clusters)

O 42.5: Poster

Mittwoch, 25. März 2009, 17:45–20:30, P2

In-situ scanning tunneling microscope growth studies of InAs and InN quantum dots during MOVPE growth — •Matthias Schmies, Raimund Kremzow, Markus Pristovsek und Michael Kneissl — TU Berlin, Institut für Festkörperphysik, EW 6-1, Hardenbergstr. 36, D-10623 Berlin, Germany

Novel optoelectronic devices, like single-photon emitters and semiconductor lasers demand a better understanding of the growth process and control of quantum dots (QD). Most optoelectronic devices are grown by metal organic vapour phase epitaxy (MOVPE) systems which allows mass fabrication for industrial applications. While QD growth has been studied intensively for InGaAs, the understanding of the mechanisms responsible for the formation of the QDs and especially of the ripening process during annealing and cooling down after growth is still relatively poor. The InGaN material system is even less understood. In order to investigate the growth dynamics and to clarify the theory of QD ripening we employed a in-situ scanning tunnelling microscope (STM) which allows measurements during MOVPE growth. In this paper we will discuss the ripening process of InAs QDs on GaAs(001):Si at 475°C. For the InAs/GaAs system the development of the stucture density agrees to the mean field theory of Lifshitz, Slyozov and Wagner (LSW-theory) of the Ostwald ripening process for three dimensional island on a two dimensional substrate. Additionally, we will present first experiments of InN QDs grown on GaN/templates sapphire using tertiarybutylhydrazine (tBHy) as nitrogen precursor.