SCANNING TUNNELING MICROSCOPY STUDIES ON THE GROWTH AND STRUCTURE OF THIN METALLIC-FILMS ON METAL SUBSTRATES

The value and applicability of scanning tunneling microscopy (STM) studies for investigating the structure and growth of thin metal films is demonstrated in model studies on two epitaxial systems, Cu/Ru(0001) and Au/Ru(0001). STM imaging gives direct access to the microscopic features of thin film growth and by following the film morphology with coverage and observing the variations with changes in the growth conditions, information on the kinetics of nucleation, diffusion barriers, and two-dimensional growth mechanisms were obtained. High resolution imaging allowed the atomic structure within the overlayers to be investigated, revealing their characteristic defects, and their mechanisms of stress accommodation between subsequent layers. These data are compared with results of earlier studies using nonlocal, averaging techniques and the often indirect conclusions drawn from those measurements.