Detection of variable tunneling rates in silicon quantum dots

TL;DR

This paper demonstrates charge sensing in silicon quantum dots using a capacitively coupled device, revealing variable tunneling rates through shifts in detector response, which is crucial for quantum information applications.

Contribution

It introduces a silicon-based charge sensing architecture capable of detecting single-electron tunneling and identifying asymmetries in tunneling rates.

Findings

Successful detection of single-electron tunneling events.

Observation of gate voltage shifts indicating variable tunneling rates.

Demonstration of the architecture's ability to reveal transport asymmetries.

Abstract

Reliable detection of single electron tunneling in quantum dots (QD) is paramount to use this category of device for quantum information processing. Here, we report charge sensing in a degenerately phosphorus-doped silicon QD by means of a capacitively coupled single-electron tunneling device made of the same material. Besides accurate counting of tunneling events in the QD, we demonstrate that this architecture can be operated to reveal asymmetries in the transport characteristic of the QD. Indeed, the observation of gate voltage shifts in the detector's response as the QD bias is changed is an indication of variable tunneling rates.