PALLADIUM CLUSTERS ON MICA - A STUDY BY SCANNING FORCE MICROSCOPY

A compact scanning force microscope with a force sensor based on the light beam deflection method was used to study palladium clusters on mica. The force microscope was equipped to measure topography of the sample surface and the friction force between the sample and the tip. The evaporation of palladium on mica was done under UHV conditions, which were closely monitored to control both the morphology and the size of the clusters. The resulting clusters were characterized by transmission electron microscopy. The samples were than transferred in air and imaged with the scanning force microscope under ambient conditions. The diameter to height ratio near 10 and the truncated triagonal shapes of the palladium clusters agree well with the results obtained by transmission electron microscopy and with the results of a scanning tunneling microscopy study of palladium clusters on graphite. Friction images show, that the interaction between the tip and the clusters does charge them.