Towards scalable gated quantum dots for quantum information applications

A crucial pre-requisite for quantum information applications is the ability to produce a scalable quantum system that can be controllably manipulated. We present a technique that promises the practical realization of a scalable system with arrays of gated quantum dots (QDs) emitting at wavelengths suitable for fibre based quantum cryptography. We show how the random nature of the nucleation site for self-assembled QDs can be overcome by a nanotemplate deposition technique such that further processing around these dots can be performed. By knowing exactly where the QD is, we position electrostatic gates around the dot with better than 30 nm accuracy. With these gates and a Si n-doped back gate, we demonstrate from both simulation and experiment that we can control the electron number of the dot via vertical electric fields. (c) 2007 Published by Elsevier B.V.