Radio frequency reflectometry and charge sensing of a precision placed donor in silicon

TL;DR

This paper demonstrates a radio frequency reflectometry technique for precise charge sensing of a single phosphorus donor in silicon, offering high bandwidth and scalable donor control for quantum computing.

Contribution

It introduces a RF reflectometry method to detect donor charge transitions, replacing traditional transistors with a single terminal dispersive reservoir for improved scalability.

Findings

RF reflectometry detects donor electron transitions at all charge degeneracy points.

The method achieves a donor neutral charging energy of approximately 62 meV.

The approach enables high bandwidth, scalable donor readout in silicon quantum devices.

Abstract

We compare charge transitions on a deterministic single P donor in silicon using radio frequency reflectometry measurements with a tunnel coupled reservoir and DC charge sensing using a capacitively coupled single electron transistor (SET). By measuring the conductance through the SET and comparing this with the phase shift of the reflected RF excitation from the reservoir, we can discriminate between charge transfer within the SET channel and tunneling between the donor and reservoir. The RF measurement allows observation of donor electron transitions at every charge degeneracy point in contrast to the SET conductance signal where charge transitions are only observed at triple points. The tunnel coupled reservoir has the advantage of a large effective lever arm (~35%) allowing us to independently extract a neutral donor charging energy ~62 +/- 17meV. These results demonstrate that we can replace three terminal transistors by a single terminal dispersive reservoir, promising for high bandwidth scalable donor control and readout.