ATOMIC-FORCE AND SCANNING-TUNNELING-MICROSCOPY ANALYSIS OF PALLADIUM AND SILVER NANOPHASE MATERIALS

Atomic force and scanning tunneling microscopy images of nanophase pal ladium and silver materials taken on various length scales are present ed. The samples show a conformational packing of individual nanometer- sized clusters. In the case of silver, islands of clusters are observe d on micrometer length scales. The islands are very flat and separated by deep crevices. The grains (clusters) within the islands are closel y packed with shapes adjusting to the neighboring grains. The islands are compact, either equiaxed or oblong in shape. Average island diamet ers of 200-300 nm and average grain sizes of 20-50 nm were measured. T he height variations on the islands are between 5 and 15 nm. The crevi ces are between 200 and 400 nm deep. In the case of palladium, the clu sters are more uniformly packed and do not appear to be agglomerated i n islands. Palladium grain sizes typically of 15 nm were measured alon g with corrugations of 10 nm in the closely packed areas.