Fast tunnel rates in Si/SiGe one-electron single and double quantum dots

TL;DR

This paper demonstrates the fabrication and measurement of Si/SiGe quantum dots with fast tunnel rates, enabling improved control for quantum computing applications through charge sensing and pulsed gate techniques.

Contribution

It introduces a method to achieve and verify fast tunnel rates in Si/SiGe quantum dots, addressing challenges posed by the large electron effective mass.

Findings

Successful fabrication of one-electron quantum dots in Si/SiGe

Identification of tunnel rate signatures via charge sensing

Validation of tunnel rate calibration with pulsed gate measurements

Abstract

We report the fabrication and measurement of one-electron single and double quantum dots with fast tunnel rates in a Si/SiGe heterostructure. Achieving fast tunnel rates in few-electron dots can be challenging, in part due to the large electron effective mass in Si. Using charge sensing, we identify signatures of tunnel rates in and out of the dot that are fast or slow compared to the measurement rate. Such signatures provide a means to calibrate the absolute electron number and verify single electron occupation. Pulsed gate voltage measurements are used to validate the approach.