The study of electronic properties of nanoscale systems is motivated by the increasing importance of quantum effects as electronic devices decrease in size. An important aspect is given by the limitations of scaling classical electronic devices such as the Metal-Oxide-Semiconductor Field-Effect-Transistor (MOSFET). Our studies of quantum phenomena aim at finding new ways of information processing. Our current major research interest is the exploration of ways to implement and control quantum bits (qubits) on the basis of solid state electronics and thereby lay the ground work for a future quantum information technology. In order to allow quantum information processing it is necessary to couple an array of such qubits in a controlled way. There exist many interesting efforts to achieve this task in different areas of physics. However, an important advantage of our solid state based two-dimensional nanoscale devices is their possible fabrication by well established industrial methods with ever increasing accuracy. In principal, this allows scalability regarding the number of coupled qubits.

Quantum dots, zero-dimensional systems containing a distinct number of electrons, sometimes referred to as artificial atoms, are a promising candidate for the realization of qubits. We fabricate quantum dot devices by selectively depleting a two-dimensional electron system (2DES) embedded within a GaAs/AlGaAs-heterostructure. Application of negative voltages to nanoscale metal gates on the surface of the heterostructure modulates the local potential and thereby restricts the mobility of electrons whithin the 2DES beneath these top gates.