Catalystlike behavior of Si adatoms in the growth of monolayer Al film on Si(111)

The formation mechanism of monolayer Al(111)1 x 1 film on the Si(111) root 3 x root 3-Al substrate was studied by scanning tunneling microscopy and first-principles calculations. We found that the Si adatoms on the root 3 x root 3-Al substrate play important roles in the growth process. The growth of Al-1 x 1 islands is mediated by the formation and decomposition of SiAl2 clusters. Based on experiments and theoretical simulations we propose a model where free Si atoms exhibit a catalystlike behavior by capturing and releasing Al atoms during the Al film growth. (c) 2010 American Institute of Physics. [doi:10.1063/1.3455231]