A key requirement for quantum computing, in particular for a scalable quantum
computing architecture, is a fast and high-fidelity qubit readout. For
semiconductor based qubits, one limiting factor is the output swing of the
charge sensor. We demonstrate GaAs and Si/SiGe asymmetric sensing dots (ASDs),
which exceed the response of a conventional charge sensing dot by more than ten
times, resulting in a boosted output swing of 3mV. This
substantially improved output signal is due to a device design with a strongly
decoupled drain reservoir from the sensor dot, mitigating negative feedback
effects of conventional sensors. The large output signal eases the use of very
low-power readout amplifiers in close proximity to the qubit and will thus
render true scalable qubit architectures with semiconductor based qubits
possible in the future.Comment: 8 pages, 7 figure