We demonstrate the trapping of electrons propagating ballistically at far-above-equilibrium energies in GaAs/AlGaAs heterostructures in high magnetic field. We find low-loss transport along a gate-modified mesa edge in contrast to an effective decay of excess energy for the loop around a neighboring, mesaconfined node, enabling high-fidelity trapping. Measuring the full counting statistics via single-charge detection yields the trapping (and escape) probabilities of electrons scattered (and excited) within the node. Energetic and arrival-time distributions of captured electron wave packets are characterized by modulating tunnel barrier transmission.

No abstract

The robust and reproducible formation of a quantum dot is key for the development of tunable barrier single-electron pumps as a future quantum current standard. We investigate the fabrication process and perform electrical characterizations at cryogenic temperatures of quantum dots realized in a GaAs/AlGaAs heterostructure with lateral potential confinement by a combination of a shallow-etch technique and metallic top-gates. Stable geometric parameters of the lithography (5% deviation) in combination with a homogeneous heterostructure resulted in the robust and reproducible quantum dot formation for 37 out of 39 tested devices.

No abstract

No abstract