NEW CONCEPTS FOR CONTROLLED HOMOEPITAXY

On the basis of a kinetic growth model we discuss new methods to grow atomically flat homoepitaxial layers in a controlled way. The underlyi ng principle of these methods is to change the growth parameters durin g growth of an atomic layer in such a way that nucleation on top of a growing layer is suppressed, and thus, layer-by-layer growth is achiev ed. Experimentally, this can be realized by changing the substrate tem perature or deposition rate during monolayer growth in a well-defined way. The same can be achieved at constant temperature and deposition r ate by simultaneous ion bombardment during the early stages of growth of a monolayer, or by adding suitable surfactants to the system. Model experiments on Ag(lll) and on Cu(lll) using thermal energy atom scatt ering and scanning tunneling microscopy demonstrate the success of the se methods.