Regensburg 2016 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 15: Quantum Dots and Wires: Fabrication and Devices
HL 15.4: Vortrag
Montag, 7. März 2016, 15:30–15:45, H16
Growth and structure of In0.5Ga0.5Sb quantum dots on GaP — •Elisa Maddalena Sala1, Gernot Stracke1, Sören Selve2, Tore Niermann2, Michael Lehmann2, Andre Strittmatter1, and Dieter Bimberg1 — 1Institut für Festkörperphysik, TU Berlin, Hardenbergstr. 36, 10623 Berlin, Germany — 2Zentraleinrichtung Elektronenmikroskopie, TU Berlin, Str. des 17. Juni 135, 10623 Berlin, Germany
III-V self-assembled QDs on GaP have recently attracted great interest for application in nanomemory cells. As demonstrated by Marent, Geller, Bimberg et al[1], such QDs can be employed as storage units in a novel type of non-volatile nanomemory, the QD-Flash. Retention times of more than 10 years for holes in In0.5Ga0.5Sb QDs embedded in a GaP matrix are predicted. Here we demonstrate for the first time the Stranski-Krastanov (S-K) growth of In0.5Ga0.5Sb QDs on GaP(001) by metalorganic vapor phase epitaxy (MOVPE). Taking advantage of the initial 2D growth of GaAs on GaP, the few GaAs layers mimic a virtual substrate for the following In0.5Ga0.5Sb deposition, playing a decisive role adjusting the surface energetics. The QD density shows a typical S-K trend, i.e. a logarithmic dependence on the amount of deposited In0.5Ga0.5Sb. High resolution cross-sectional TEM micrographs of buried QDs show a typical truncated-pyramid shape. Before supplying QD material, a short Sb-flush is used to initiate Sb incorporation. Experimental results show that Sb apparently modifies the growth kinetics by reducing the In and Ga surface diffusion length.
[1] A. Marent et al, Microelectronics Journal 40 (2009), 492-495.