Berlin 2015 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 95: Poster IV B (Quantum dots and wires: Prepration, characterization, optical properties, and transport)

HL 95.29: Poster

Donnerstag, 19. März 2015, 14:00–20:00, Poster B

Capacitance-Voltage Spectroscopy of InAs Quantum Dots Under External Applied Strain — •Sascha R. Valentin¹, Arne Ludwig¹, Dirk Reuter², and Andreas D. Wieck¹ — ¹Angewandte Festkörperphysik, Ruhr-Universität-Bochum — ²Optoelektronische Materialien und Bauelemente, Universität Paderborn

Self-assembled InAs quantumdots (QDs) are integrated in a variety of interesting optical and electronical devices and are also highly interesting from a fundamental point of view. Electric fields are often used to tune the optical and electronical properties of QDs. Recently it has been shown that external applied strain can reversibly shift the optical emission energy of QDs. Theoretical calculations indicate that the shift in the emission energy originates in the changed coulomb interaction between the charge carriers as well as in the shift of the energy levels themselves. In this project we want to measure the dependence of the interaction energies of the carriers on externally applied strain using capacitance voltage (CV) spectroscopy. In the device we present, a thin electrically contacted CV-membrane is bonded to a PMNPT-piezoelectric actuator. This allows to apply strain to the QDs and at the same time it enables electrical measurements on a QD ensemble.