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Updated: Jun 21, 2026
14:58
Silicon Metal-oxide-semiconductor Quantum Dots for Single-electron Pumping
Published on: June 3, 2015
Charge sensing and controllable tunnel coupling in a Si/SiGe double quantum dot
C B Simmons1, Madhu Thalakulam, B M Rosemeyer
1University of Wisconsin-Madison, Madison, Wisconsin 53706, USA. cbsimmons@wisc.edu
Nano Letters
|August 4, 2009
Summary
We demonstrate tunable double quantum dots in silicon, controlling the tunnel coupling between dots using gate voltage. This is key for developing silicon spin qubits.
Area of Science:
- Quantum Computing
- Condensed Matter Physics
- Semiconductor Nanostructures
Background:
- Silicon-Germanium (Si/SiGe) heterostructures are promising platforms for quantum computing.
- Fabricating and controlling double quantum dots is essential for realizing qubits.
Purpose of the Study:
- To investigate the tunability of a Si/SiGe double quantum dot.
- To measure and analyze the tunnel coupling between the quantum dots.
Main Methods:
- Integrated charge sensing measurements were performed on a Si/SiGe double quantum dot device.
- The device was tuned from a single- to a double-dot regime using gate voltages.
- Tunnel coupling (t) was extracted as a function of gate voltage.
Main Results:
- The Si/SiGe double quantum dot is tunable, transitioning between single and well-isolated double dot configurations.
- Charge sensing enabled the extraction of tunnel coupling (t) as a function of top gate voltage.
- The tunnel coupling exhibited an exponential dependence on the applied gate voltage, indicating barrier control.
Conclusions:
- Precise control over the tunnel coupling in Si/SiGe double quantum dots was achieved.
- This gate-voltage-controlled coupling is a critical advancement for manipulating spin qubits in silicon.
- The findings pave the way for scalable silicon quantum dot architectures.
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