The surface potential of the Si nanostructure on a Si (1 1 1) 7×7 surface generated by contact of a cantilever tip

A Si microstructure on a Si (1 1 1) 7×7 surface was investigated by a noncontact atomic force microscopy (ncAFM) and a scanning Kelvin probe microscopy (SKPM) in ultra high vacuum. The Si microstructure was generated by intermittent contact of a cantilever tip. It was found by the ncAFM and SKPM observations that the Si mound with a height of 1 Å and a width of 30 nm was generated, and the surface potential of the small mound was 0.1 V lower than that of the 7×7 domain. A quenched Si (1 1 1) surface was also observed by the ncAFM and SKPM. The differences in height and potential between the reconstructed 7×7 and the disordered 1×1 domains were about 1 Å and 0.1 V, respectively. Therefore, it was concluded that there appeared the disordered 1×1 structure on the surface of the Si small mound, lowering the surface potential by 0.1 V.