Dresden 2014 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 100: Metamorphic structures: Bringing together incompatible materials II (Focus session with DF)
HL 100.4: Vortrag
Donnerstag, 3. April 2014, 16:00–16:15, POT 251
Measurement of strain in the InGaN/GaN heterogeneous nanostructures — •Tomaš Stankevič1, Simas Mickevičius1, Mikkel Schou Nielsen1, Robert Feidenhans’l1, Olga Kryliouk2, Rafal Ciechonski2, Giuliano Vescovi2, Zhaoxia Bi3, and Anders Mikkelsen3 — 1University of Copenhagen, Niels Bohr Institute, Copenhagen, Denmark — 2GLO AB, Lund, Sweden — 3Lund University, Nanometer Structure Consortium, Lund, Sweden
Growth and electrical properties of the core-shell nanostructures are often infulenced by the lattice mismatch induced strain. In contrast to planar films nanostructures contain multiple facets that act as independent substrates for the shell growth. In this study we present experimental results obtained by X-ray diffraction showing that the InGaN shells grown on the GaN cores are strained along each of the facets independently. Reciprocal space maps (RSMs) reveal multiple Bragg peaks corresponding to different parts of the shell strained along individual facet planes. Strained lattice constants were found from the peak positions. Vegard’s law and Hooke’s law for an anisotropic medium were applied in order to find the composition and strain in the InGaN shell. Simple atomistic kinematic simulations of the RSMs showed good agreement with the experimental data. We conclude that 8 nm the InGaN shells of up to 27% indium composition were nearly fully strained bixially along each of the 1010 facets of the nanowires and the 1011 facets of the nanopyramids.