Barriers for hydrogen atom diffusion on the Si(100)-2×1 surface

Abstract

Density functional theory is used in conjunction with cluster models to calculate activation energies for diffusion of H atoms on the Si(100)-2×1 surface. The activation energy for diffusion along the surface dimer rows is calculated to be 52 kcal/mol, and that for diffusion perpendicular to the dimer rows is even higher, leading us to conclude that H-atom diffusion on the Si(100)-2×1 surface probably does not play an important role in the H2 desorption process. The activation energies obtained in the present study are appreciably higher than those obtained from prior calculations using density functional theory. A major factor causing these differences is our use of the Becke3-LYP functional rather than the Becke–Perdew functional, used previously.