Current–voltage characteristics of the partially Ga-terminated Si (111) surface studied by scanning tunneling microscopy

We investigated the current–voltage (I–V) characteristics of the Si (111) surface partially terminated by Ga atoms by using scanning tunneling microscopy. On the surface, Si (111) 7×7 and Si (111) √3×√3 Ga terraces alternated. The I–V curves of the 7×7 terraces exhibited semiconductive features, not metallic. The √3×√3 Ga terraces on the surface had narrower surface band gaps than usual √3×√3 Ga surfaces. These features could be explained by taking into account the adatom replacement between Ga and Si adatom sites. An amorphous Si layer was deposited on the surface after Sb was selectively adsorbed on the 7×7 terraces. The alternate structure was preserved after recrystallization of the Si layer. © 1998 American Institute of Physics.