In-plane Gate Single Electron Transistor Fabricated by AFM Lithography

Abstract

Coulomb blockade is observed in semiconductor quantum dotsfabricated by scanning probe lithography. We demonstrate thatby combining top gates with in-plane gates, the lithographicshape of a dot can be transferred into the electron gas withhigh accuracy. Furthermore, by applying voltages to the in-plane gates, the number of electrons on the dot can be changedby more than 70 without changing its shape. Transportmeasurements in high magnetic fields and with positive topgate voltages applied indicate that the potential walls of thenanostructure can be made very steep.