Formation of the 5×5 reconstruction on cleaved Si(111) surfaces studied by scanning tunneling microscopy

The transformation of cleaved Si(111)2×{}1 surfaces into apparent 1×{}1, 5×{}5, and 7×{}7 structures has been studied with the scanning tunneling microscope. Two reaction paths are identified, one proceeding through a disordered adatom arrangement into the 7×{}7 structure, and the other proceeding directly from 2×{}1 into the 5×{}5 structure. Near a nucleation site (step or domain boundary), the first path is favored due to the abundance of adatoms on the surface, and far from a nucleation site the second path dominates.