Surface phase transition of Cu/Si(1 1 1)-(5 × 5) by scanning tunnelling microscopy and photoemission study

Abstract

The phase transition process from the Si(1 1 1)-(7 × 7) surface to the Cu/Si(1 1 1)-(5 × 5) surface structure has been studied by scanning tunnelling microscopy and synchrotron radiation photoemission spectroscopy. The nucleation and growth of Cu/Si(1 1 1)-(5 × 5) on the Si(1 1 1)-(7 × 7) surface progress gradually with the increase in Cu coverage. Cu deposition on the Si(1 1 1)-(7 × 7) surface at room temperature may only involve the saturation of the surface dangling bonds, whereas a new surface phase of Cu/Si(1 1 1)-(5 × 5) is formed upon annealing, which saturates at a Cu coverage of 0.9 ML. Our experiments clearly show the surface phase transition process of the (5 × 5) structure as a function of the Cu coverage and provide useful insight into the Cu/Si(1 1 1)-(5 × 5) structure. © 2008 IOP Publishing Ltd.