BUILDING NANOSTRUCTURES BY CONTROLLED MANIPULATION OF SINGLE ATOMS AND MOLECULES WITH THE SCANNING TUNNELING MICROSCOPE

Our present experiences in manipulating single atoms and molecules on solid surfaces by using the tip of a scanning tunneling microscope (ST M) are reviewed. The construction and performance characteristics of o ur temperature variable STM is shortly described. which allows investi gations in the temperature range between 15 and 300 K. As example for horizontal manipulation, in which the adatoms or admolecules are pulle d along the surface by the STM tip; and the formation of man-made surf ace structures, the formation of the letters 'F' and 'U', which form t he logo of our university is presented. The adspecies used in these ex periments are CO molecules and the substrate a Cu(211) surface. An exa mple of vertical manipulation, in which an adparticle is picked up by the tip, carried to another place and released back to the surface, co ncerns Xe on the same substrate. The latter technique allows also to v ary the chemical composition of the tip apex in a well-defined manner. Consequences in imaging the surface with tips of different compositio ns are presented and discussed. Finally, STM observations of ordered h igh density phases of CO on the Cu(211) substrate are discussed.