THE EFFECTS OF ONE DIMENSIONAL DISORDER IN RARE-EARTH SILICIDE/SI (111) EPILAYER SURFACES ON RECIPROCAL SPACE AND ELECTRON DIFFRACTION

The effects of disorder occurring between self-assembled linear surface structures, characteristic of sub-monolayer epitaxial silicides of Er and Gd on Si(111), have been analyzed by low energy (LEED) and reflection high energy (RHEED) electron diffraction. The observed (2×1) antiphase domains, and random registry shifts between adjacent adsorbate atomic chains, caused appearance of diffuse intensity planes in the surface reciprocal space, and disappearance of half-order satellites in diffraction patterns of a surface reconstruction identified by scanning tunneling microscopy (STM) as Si(111)-(3×”2”)-Gd, respectively. The diffuse intensity planes in the reciprocal space can be visualized in diffraction patterns, as straight (in LEED) or arched (in RHEED) streaks.