SKM 2021 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 19: Poster Session IV
HL 19.12: Poster
Donnerstag, 30. September 2021, 13:30–16:30, P
Coulomb Blockade at room temperature of self-assembled GaN quantum dot ensembles, measured via Capacitance-Voltage spectroscopy — •Carlo Alberto Sgroi1, Julien Brault2, Jean-Yves Duboz2, Philippe Vennéguès2, Sébastien Chenot2, Arne Ludwig1, and Andreas D. Wieck1 — 1Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, D-44780 Bochum, Germany — 2CNRS - CRHEA, Rue Bernard Grégory, 06560 Valbonne, France
We present capacitance voltage (C(V)) measurements at room temperature of charge-tunable self-assembled wurtzite GaN quantum dots (QDs) in an AlxGa1-xN matrix grown by MBE. GaN and its alloys have excellent properties such as their thermal stability, high thermal conductivity and wide bandgap energies which make them an ideal candidate for next-generation GaN-based power devices at elevated temperatures. Single-photon sources operating at up to 350 K are already possible1. Due to polarization and strain effects in wurtzite GaN/AlxGa1-xN heterostructure layers, the band structure is different for the cross section with the GaN QDs and the GaN Wetting Layer (WL) on which the QDs are formed. Large electric fields and defect-assisted electron hopping promote charge transfer through the WL. Performing C(V) spectroscopy at 300 K on an AlGaN-Schottky diode structure with embedded GaN QDs, single-electron discharging in the C(V) spectrum and a Coulomb blockade energy of about 70 meV are measured.
[1] Holmes, M. J., et al. ACS Photonics 3, 543-546 (2016).