Nanoscale dislocation patterning in Bi(111)/Si(001) heteroepitaxy

In: Surface Science, Jg. 603 (2009) ; Nr. 13, S. 2057-2061
ISSN: 0039-6028
Zeitschriftenaufsatz / Fach: Physik
Fakultät für Physik » Experimentalphysik
Abstract:
Continuous, atomically flat, and epitaxial Bi(1 1 1) films could be grown on Si(0 0 1). The inherent strain of 2.3% between the Bi(1 1 1) and Si(0 0 1) lattices is relieved by the formation of a grating like one-dimensional misfit dislocation array at the heterointerface. The lattice distortions around each dislocation give rise to a pronounced height depression Δh = 0.12 nm of the surface, which results in a spot splitting in low-energy electron diffraction and a height contrast in scanning tunneling microscopy (STM). Using STM surface profiles across these depressions, the Burgers vector of the underlying isolated non-interacting dislocations is estimated to be 0.377 nm. For thicker Bi films the ordering of the dislocation network is increased. This reflects an increase of repulsive interaction between neighboring dislocations.