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HL: Halbleiterphysik

HL 30: Quantum dots and wires: Transport properties II

HL 30.4: Vortrag

Mittwoch, 29. März 2006, 19:00–19:15, HSZ 01

Bias voltage controlled threshold hysteresis in GaAs/AlGaAs quantum-wire transistors with embedded InGaAs quantum dots — •Christian R. Müller, Lukas Worschech, and Alfred Forchel — Technische Physik, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany

We have studied the threshold hysteresis of quantum-wires realized by electron beam lithography and wet chemical etching on the basis of a GaAs/AlGaAs heterostructure with InGaAs quantum dots in the AlGaAs spacer. Threshold shifts are due to charging and discharging of the quantum dots and can be controlled electrically by the side-gates. We have observed that the threshold hysteresis between up- and down-sweeps of the side-gate voltage decreases with increasing bias voltage, and for a critical bias voltage the threshold hysteresis is suppressed. A change of the hysteresis sign was detected for bias voltages exceeding the critical bias voltage. As a result the memory function of the studied quantum-wire transistors can be inhibited electrically. We discuss the bias voltage dependent variation of the threshold hysteresis in terms of an interplay between the capacitive couplings of the quantum-wire, the quantum dots and the side-gates.