A Silicon Cluster Based Single Electron Transistor with Potential Room-Temperature Switching

TL;DR

This paper reports the fabrication of a silicon quantum dot single electron transistor with high charging energy, demonstrating potential for room-temperature operation and spin manipulation.

Contribution

It introduces a novel silicon quantum dot-based single electron transistor with large Coulomb energy suitable for room-temperature applications.

Findings

Charging energy up to 300 meV observed.

Large level spacing (~10 meV) enables spin control.

Zeeman splitting measured with a g-factor of 2.3.

Abstract

We demonstrate the fabrication of a single electron transistor device based on a single ultra-small silicon quantum dot connected to a gold break junction with a nanometer scale separation. The gold break junction is created through a controllable electromigration process and the individual silicon quantum dot in the junction is determined to be a Si_170 cluster. Differential conductance as a function of the bias and gate voltage clearly shows the Coulomb diamond which confirms that the transport is dominated by a single silicon quantum dot. It is found that the charging energy can be as large as 300meV, which is a result of the large capacitance of a small silicon quantum dot (1.8 nm). This large Coulomb interaction can potentially enable a single electron transistor to work at room temperature. The level spacing of the excited state can be as large as 10 meV, which enables us to manipulate individual spin via an external magnetic field. The resulting Zeeman splitting is measured and the lande factor of 2.3 is obtained, suggesting relatively weak electron-electron interaction in the silicon quantum dot which is beneficial for spin coherence time.