Dresden 2014 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 51: Quantum Wires: Optical Properties (organized by HL)
TT 51.6: Vortrag
Dienstag, 1. April 2014, 15:45–16:00, POT 112
Nanospectroscopic imaging of twinning superlattices in individual Beryllium-doped GaAs/AlGaAs core-shell nanowires — •Alexander Senichev1, Igor Shtrom2, Vadim Talalaev1,3, George Cirlin2,4, Christoph Lienau5, Jörg Schilling3, and Peter Werner1 — 1Max-Planck-Institut für Mikrostrukturphysik, Halle, Germany — 2St. Petersburg Academic University RAS, St. Petersburg, Russia — 3Martin-Luther-Universität, ZIK "SiLi-nano", Halle, Germany — 4Ioffe Physico-Technical Institute, St. Petersburg, Russia — 5Institut für Physik, Carl von Ossietzky University, Oldenburg, Germany
We report on subwavelength-resolution near-field photoluminescence (PL) spectra and transmission electron microscopy (TEM) images taken from the very same single p-GaAs/AlGaAs core-shell nanowire grown on silicon.By correlation with the TEM images, we distinguish between the emission spectra of pure ZB-type regions and those of periodic twinning plane superlattices (TSL). Emission from the ZB region is governed by direct interband recombination whereas the TSL spectra are split into two peaks, separated in energy by the hole confinement at a single WZ-type quantum disk. Blue-shifts of the local emission spectra reveal electron quantum confinement in twinning superlattices and allow us to trace spatial variations of the TSL period by all-optical means. Our results provide direct and quantitative insight into the correlations between morphology and optics of TSL nanowire and hence present an important step towards band gap engineering of GaAs nanowires by controlled crystal phase formation.