First-principles molecular-dynamics calculations and STM observations of dissociative adsorption of Cl 2 and F 2 on Si(0 0 1) surface

Abstract

We have studied the dissociative adsorption process of halogen molecules (Cl 2 and F 2) on the Si(0 0 1) surface by first-principles molecular-dynamics (FPMD) calculations and scanning tunneling microscopy (STM) observations. From FPMD calculations, we demonstrate that Cl 2 and F 2 molecules adsorb dissociatively at dangling bonds of a buckled dimer with no energy barrier, so that the buckled dimer becomes geometrically flat. In addition, STM observations show that the dissociative adsorptions of Cl 2 and F 2 induce buckled dimers at the S A step on the Si(0 0 1)-(2×1) surface to become symmetric dimers, in good agreement with the results of FPMD calculations.