Quantum size effects in the surface energy of Pb/Si(111) film nanostructures studied by surface x-ray diffraction and model calculations
- Department of Physics, University of Illinois at Urbana-Champaign, 1110 W. Green Street, Urbana, Illinois 61801-3080 (United States)
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, 104 S. Goodwin Avenue, Urbana, Illinois 61801-2902 (United States)
We have used surface x-ray diffraction from a synchrotron source, along with models based upon a free-electron gas confined to a quantum well, to study quantum size effects in the surface energy of ultrathin Pb films grown on pretreated Si(111) substrates. Films grown at 110 K are smooth, but as they are annealed to near room temperature, their morphology is observed evolving through various metastable states and eventually to a roughened state in local equilibrium. Strong variations in the stability of different island heights are observed, consistent with quasibilayer oscillations in the surface energy found from the theoretical free-electron calculations. By analyzing the quasiequilibrium distribution of thicknesses, empirical information on the film surface energy is obtained for a wide range of thicknesses. The morphological annealing behavior of the films is also found to be explained by the deduced surface energy.
- OSTI ID:
- 20719336
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Journal Name: Physical Review. B, Condensed Matter and Materials Physics Journal Issue: 7 Vol. 72; ISSN 1098-0121
- Country of Publication:
- United States
- Language:
- English
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