AVS 46th International Symposium
    Surface Science Division Wednesday Sessions
       Session SS-WeP

Paper SS-WeP15
Real-time VT-STM Studies of Dewetting Processes: Ag/Si(111)

Wednesday, October 27, 1999, 5:30 pm, Room 4C

Session: Poster Session
Presenter: K. Th@um u@rmer, University of Maryland
Authors: K. Th@um u@rmer, University of Maryland
E.D. Williams, University of Maryland
J.E. Reutt-Robey, University of Maryland
Correspondent: Click to Email
Under typical MBE-conditions thin film morphology is often limited by kinetics. An excellent model system for film growth proceeding far from equilibrium is silver, deposited at room temperature on Si(111) (see review@footnote1@). At a mean film thickness of 1nm, the substrate is completely covered by worm-like structures. Using a variable temperature STM, we have studied the transformation of these metastable structures into equilibrium shaped hexagonal crystallites. By tracking the annealing process in real time, we encounter an astonishing variety of transition shapes. At ~200C the onset of de-wetting exposes substrate areas with a root3 x root3 reconstruction. The higher mobility on these denuded areas acts as a positive feedback, accelerating the decay of adjacent structures. At ~300 C the morphology is dominated by 500 nm wide and 100 nm high crystallites, exhibiting networks of partial dislocations on their (111)-top facets. This work has been supported by the NSF-MRSEC at University of Maryland under grant #DMR-96-32521. @FootnoteText@ @footnote 1@ H.Neddermeyer, Critical Rev. in Solid State and Material Science 16(5),309 (1990) 29, 30, 53-55, 57, 68.