Atomically perfect bismuth lines on Si(001)

Abstract

Atomically perfect bismuth lines form on Si(001) by a selective desorption process around the temperature at which most of the bismuth desorbs from bismuth epitaxial layers. The lines are perpendicular to the silicon dimer rows; they are 1 nm wide and can be hundreds of nm long in a flat Si(001) surface. They are utterly free of kinks or other defects. In our proposed model three silicon dimers in the surface are replaced with two Bi dimers, with a rebonded missing dimer defect between them. It is suggested that the lines are straight because of kinetic reasons rather than thermodynamic ones -- they form straight and are unable subsequently to kink.