Morphology of step structures on CeO2(111)

The morphology of step structures on the CeO2(111) surface is studied by dynamic scanning force microscopy (SFM) operated in the noncontact mode. The surface exhibits hexagonal islands and pits of O–Ce–O triple layer height with steps mostly enclosing an angle of 120°. Atomically resolved images reveal that the (111) surface almost exclusively exhibits alternating steps having (110) and (001) facets. Kink sites and missing oxygen atoms at step edges are identified to be the dominating defective sites at step edges. It is demonstrated that low coordinated oxygen atoms at step edges can be removed by the scanning SFM tip.