So far miniaturisation in microelectronics has lead to ever smaller semiconductor structures with structural sizes of less than 200 nm. This meant a reduction of costs and, at the same time, an increase in the yield and speed of components and a reduction of power consumption. However, these positive aspects of miniaturisation will no longer predominate in the future, as you can foresee that structuring processes in the nanometer range will be relatively slow and require enormous expenditure. Moreover it is not yet clear whether physical phenomena, in particular quantum effects, allow components to be scaled down to ever smaller structures. The smallest electronic component is the single-electron transistor, which is in some ways similar to a field-effect transistor, but which displays electronic features of a new quality. Basic research in single-electron transistors is carried out at different research institutes with structural sizes of less than 30 nm being realised in semiconductor material. These components reach dimensions of the size of clusters or molecular systems. Consequently the question is being discussed if nanoelectronic components should rather be realised by a controlled build-up on the molecular level (bottom-up process) than by reducing the size of solids (top-down process). Today there are already laboratory models of one-dimensional wires and transistors that are for example based on natural nanotubes. The lecture will give you a general idea of the physics and the manufacture of nanoelectronic components.