QUASI-ONE-DIMENSIONAL CAF2 ISLANDS FORMED ON SI(001) BY MOLECULAR-BEAM EPITAXY

Quasi-one-dimensional CaF2 islands, 5-10 nm in both width and height a nd several mu m in length, have been grown on Si(001) by molecular bea m epitaxy. Using conventional and high resolution transmission electro n microscopy we show that the islands grow in two symmetry-equivalent, {011} orientations and are bounded by {111} facets. The unusual islan d morphology is attributed to a low density of nucleation sites, the s mall lattice mismatch, and the anisotropic CaF2 surface energy. (C) 19 96 American Institute of Physics.