Single-electron transistors with a self-assembled quantum dot
Single-electron transistors with a self-assembled quantum dot are fabricated by direct epitaxial growth on patterned substrates. A self-assembled quantum dot is formed during the deposition of an heterostructure on a bow-tie-shaped constriction, pre-patterned on a GaAs substrate. The self-assembled quantum dot is located in the centre of the constriction and is coupled via tunnelling barriers, also fabricated within the same growth process, to electrical leads. The fabricated devices allow switching with single electrons up to temperatures of 6 K by applying a voltage to an in-plane gate, which is also fabricated during the epitaxial growth. The structure of the devices is also characterized using scanning-electron and atomic-force microscopy.