Regensburg 2022 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 25: Poster 1
HL 25.77: Poster
Mittwoch, 7. September 2022, 18:00–20:00, P2
Building charge detection in indium antimonide nanowires for scanning tunneling microscopy using gate-defined quantum dots — •Kanji Furuta1, Felix Jekat1, Benjamin Pestka1, Sasa Gazibegovic2, Diana Car2, Sebastian Heedt3, Marcus Liebmann1, Thomas Schäpers3, Erik Bakkers2, and Markus Morgenstern1 — 1II. Phys. Inst. B, RWTH Aachen Univ., Germany — 2Dept. of Appl. Phys., Eindhoven Univ., The Netherlands — 3PGI-9, FZ Jülich, Germany
InSb nanowires are investigated with respect to suitability as a charge detector to be combined with scanning tunneling microscopy. Mechanically exfoliated hexagonal boron nitride (h-BN) as a dielectric is placed onto bottom finger gates (50 nm wide, 30 nm spacing). The nanowires are then aligned and placed mechanically onto h-BN. We present transport measurements on gate-defined quantum dots at temperatures down to 300 mK. Due to the dielectric, the time stability of our device improved to around 5 µeV/h. The charge stability diagram shows Coulomb diamonds with a charging energy of 2.5 meV and an orbital energy of 0.3 meV. Depending on the gate and magnetic field, additional transport channels are occasionally observed, causing additional lines in the charge stability diagram and a shift of the Coulomb peak pattern around a magnetic field of ≈ 400 mT. This points to the presence of an unintentional second quantum dot in the gate region. Different configurations are discussed in terms of their coupling to the leads and the main dot, and their effects on charge detection.