Berlin 2008 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 33: III-V semiconductors II

HL 33.15: Talk

Wednesday, February 27, 2008, 18:15–18:30, EW 201

Selective etching of independent contacts in a double quantum-well structure: quantum-gate transistor — •Stefan Lang, Lukas Worschech, Monika Emmerling, Micha Strauß, Sven Höfling, and Alfred Forchel — Technische Physik, Physikalisches Institut, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany

Double GaAs quantum wells (QWs) embedded between modulation-doped AlGaAs barriers with different Al contents were grown by molecular beam epitaxy.Independent electric contacts to each well were realized by applying different etching techniques without substrate removal. In particular the lower quantum well was electrically pinched off by a local undercut of the lower AlGaAs barrier. The upper QW was locally depleted by top etched trenches. Transistor operation of quantum wires defined in such bilayers is demonstrated at room temperature with one GaAs serving as channel controlled by the other nearby GaAs layer as efficient gate.