Berlin 2018 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 24: Poster Session II
HL 24.16: Poster
Tuesday, March 13, 2018, 18:30–20:30, Poster F
Energy Tuning of Self-Organised Quantum Dot Ensembles via Piezomechanical Strain — •Nikolai Bart1, Sascha Valentin1, Arne Ludwig1, Andreas Wieck1, Yan Chen2, Fei Ding2, and Oliver Schmidt2 — 1Lehrstuhl für Angewandte Festkörperpyhsik, Ruhr-Universität Bochum — 2Institute for Integrative Nanosciences, IFW Dresden
Beside temperature, magnetic and electric fields tuning of the energetic states in quantum dots (QDs) for opto-electronic applications, piezomechanical strain offers an additional tuning knob. We present photoluminescence (PL) and capacitance-voltage (CV) spectroscopy measurements of bi-axially strained self-organised InAs QD ensembles on a piezoelectric actuator. While for PL at room temperature a redshift of 5 meV and inhomogeneous ensemble linewidth broadening of 20 % can be observed when the piezo actuator is biased with 550 V (tensile strain), this effect is diminished at 77 K. CV spectroscopy at 4.2 K on the other hand exhibits a shift in the opposite direction, towards higher gate voltages. While the PL redshift is well documented by others and can be attributed to an altered QD confinement potential due to piezo strain induced morphological changes, the CV results require additional research, which may be provided by introducing a magnetic field to the CV measurements and by wave function mapping.