Self-organized growth of quantum dot-tunnel barrier systems

Abstract

Surface selective epitaxial growth on patterned substrates is used to fabricate quantum dot-tunnel barrier systems, which can be used as single-electron transistor devices. In the centre of a pre-patterned constriction a self-assembled GaAs quantum dot embedded in barrier material is formed during the molecular beam epitaxial growth of an Al0.33Ga0.67As/GaAs heterostructure. The quantum dot is connected via self-aligned tunnelling barriers to source and drain electrodes. In-plane-gate electrodes are also realized within the epitaxial growth process. The paper describes the fabrication process of the device and the characterization of the direct grown quantum dot-tunnel barrier system using scanning-electron microscopy, atomic-force microscopy and transport spectroscopy.