Regensburg 2007 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 11: Quantum dots and wires: Transport properties I

HL 11.10: Talk

Monday, March 26, 2007, 17:15–17:30, H15

Source gating enhanced threshold hysteresis in electron Y-branch switches with quantum dots — •Christian R. Müller, Lukas Worschech, Philipp Höpfner, and Alfred Forchel — Technische Physik, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany

On the basis of modulation doped GaAs/AlGaAs heterostructures with self-assembled InGaAs quantum dots embedded in the undoped spacer, Y-branched nanojunctions controlled by four independent side-gates were fabricated by electron beam lithography and etching techniques. Charging of the quantum dots in the Y-junction is demonstrated by pronounced threshold hysteresis. Interestingly, the gate voltage at which the quantum dots are discharged shifts to lower values with increasing Fermi energy of the source indicating that the charges in the sources have a considerable gate effect on the channel. In particular, by switching the Fermi energy of the source a drastically enhanced threshold hysteresis was observed.