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HL: Fachverband Halbleiterphysik
HL 11: Quantum information systems: mostly quantum dots
HL 11.6: Vortrag
Montag, 11. März 2013, 13:15–13:30, H16
Undoped Si/SiGe heterostructures for field-effect devices — •Simon Pfaehler1,2, Johannes Kierig1, Andreas Wild1,2, Christoph Buhlheller1,2, Gerhard Abstreiter2, Kentarou Sawano3, and Dominique Bougeard1 — 1Institut für Experimentelle und Angewandte Physik, Universität Regensburg, Germany — 2Walter Schottky Institut, Technische Universität München, Garching, Germany — 3Advanced Research Laboratories, Tokyo City University, Japan
Two-dimensional electron systems (2DES) in modulation doped heterostructures represent a promising building block for the development of electrostatically defined spin qubits. The hyperfine interaction with the nuclear spin bath being a dominant qubit decoherence mechanism, Si/SiGe heterostructures have been receiving steadily increasing attention for building devices almost free of nuclear spin carrying isotopes. However, such modulation doped heterostructures still suffer from fluctuating charges due to the presence of ionized dopants which can also in the end limit the spin decoherence time.
One possible way to reduce fluctuating charges is to avoid doping in Si/SiGe heterostructures and induce a 2DES capacitively. In this contribution, we report on the realization and experimental characterization of undoped Si/SiGe heterostructures designed for the implementation of electrostatically defined double quantum dots. A global top gate is used to operate this device via field effect to induce a 2DES in the undoped Si quantum well. The electronic behavior is additionally studied in band structure simulations.