In-plane gate single-electron transistor in Ga[Al]As fabricated by scanning probe lithography

TL;DR

This paper reports the fabrication of a single-electron transistor in Ga[Al]As using scanning probe lithography, demonstrating precise control of electron number and coupling with observable Coulomb blockade oscillations.

Contribution

It introduces a novel fabrication method for in-plane gate single-electron transistors with high pattern transfer accuracy and stable dot shape during tuning.

Findings

High accuracy pattern transfer to electron gas at positive top-gate voltages

Pronounced Coulomb blockade oscillations observed

Dot shape remains stable during in-plane gate tuning

Abstract

A single-electron transistor has been realized in a Ga[Al]As heterostructure by oxidizing lines in the GaAs cap layer with an atomic force microscope. The oxide lines define the boundaries of the quantum dot, the in-plane gate electrodes, and the contacts of the dot to source and drain. Both the number of electrons in the dot as well as its coupling to the leads can be tuned with an additional, homogeneous top gate electrode. Pronounced Coulomb blockade oscillations are observed as a function of voltages applied to different gates. We find that, for positive top-gate voltages, the lithographic pattern is transferred with high accuracy to the electron gas. Furthermore, the dot shape does not change significantly when in-plane voltages are tuned.