Orientation dependence of strained-Ge surface energies near (001): role of dimer-vacancy lines and their interactions with steps.
Recent experiments and calculations have highlighted the important role of surface-energy (gamma) anisotropy in governing island formation in the Ge/Si(001) system. To further elucidate the factors determining this anisotropy, we perform atomistic and continuum calculations of the orientation dependence of gamma for strained-Ge surfaces near (001), accounting for the presence of dimer-vacancy lines (DVLs). The net effect of DVLs is found to be a substantial reduction in the magnitude of the slope of gamma vs orientation angle, relative to the highly negative value derived for non-DVL, dimer-reconstructed, strained-Ge(001) surfaces. The present results thus point to an important role of DVLs in stabilizing the (001) surface orientation of a strained-Ge wetting layer.
Moore
C J
CJ
Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA.
Retford
C M
CM
Beck
M J
MJ
Asta
M
M
Miksis
M J
MJ
Voorhees
P W
PW