Regensburg 2013 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 41: Quantum dots and wires: Preparation and characterization

HL 41.3: Vortrag

Dienstag, 12. März 2013, 11:45–12:00, H15

MOVPE growth of InGaAs quantum dots on GaP for nanomemory cells — •Gernot Stracke, Bertram Jaeger, Tobias Nowozin, Leo Bonato, Sven Rodt, Andrei Schliwa, Andre Strittmatter, Christopher Prohl, Andrea Lenz, Holger Eisele, Udo W. Pohl, and Dieter Bimberg — Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstraße 36, 10623 Berlin, Germany

InGaAs quantum dots (QDs) are realized on GaP(001) substrates by metalorganic vapor phase epitaxy. A prospective application of such QDs is the fabrication of nanomemory cells. These QD memory cells promise to combine the fast write and erase times of a DRAM with the non-volatility of a Flash memory. By replacing GaAs with GaP as matrix material, an extension of the storage time of holes in InAs QDs at room temperature from 0.5 ns to 1 s can be expected. Additionally, GaP offers the potential of integration with Si, since GaP and Si have almost the same lattice constant. The growth of coherent InGaAs QDs on GaP is found to depend critically on the deposition of a thin layer of GaAs prior to QD growth. On a bare GaP substrate the growth proceeds purely two-dimensional even for high indium concentrations of up to 83%. In contrast, Stranski-Krastanow growth of InGaAs QDs is observed already for indium concentrations as low as 25% when the surface of the GaP substrate is covered by 3 monolayers (ML) of GaAs. In_0.25Ga_0.75As/3 ML GaAs/GaP QDs exhibit luminescence around 1.9 eV. The storage time of holes in In_0.25Ga_0.75As/3 ML GaAs/GaP QDs is estimated to 3 µs at room temperature.