BARRIERS FOR HYDROGEN-ATOM DIFFUSION ON THE SI(100)-2X1 SURFACE

Density functional theory is used in conjunction with cluster models to calculate activation energies for diffusion of H atoms on the Si(100)-2X1 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)-2X1 surface probably does not play an important role in the H 2 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. © 1995 American Institute of Physics.