STM measurements of atomic-scale dynamics of atoms and dimers on the Si(001) surface
- Sandia National Labs., Albuquerque, NM (United States)
Diffusing Si monomers and dimers adsorbed on the Si(001) crystal surface can be trapped between two surface defects that act as hard-wall reflecting barriers. Because monomers and dimers migrate only along one crystal direction, they are confined to diffuse only among the accessible lattice sites between the reflecting walls. We measure the kinetics of confined monomers and dimers using scanning tunneling microscopy (STM) in order to extract lattice-site specific energetics, both diffusion barriers and binding free energies. Si monomers are clearly observed in empty-state images, while remaining virtually invisible in filled-state images. We identify specific lattice sites at which monomers are strongly bound and measure the binding activation barrier at these sites. In addition, the interaction free energies of dimers with various types of reflecting walls are measured as a function of distance from the walls. The quantitative measure of lattice-site specific energy parameters not only serve as inputs to realistic simulations and calculations, but also enable the validation and refinement of such calculations.
- Research Organization:
- Sandia National Laboratory
- DOE Contract Number:
- AC04-94AL85000
- OSTI ID:
- 559961
- Report Number(s):
- CONF-970443--
- Country of Publication:
- United States
- Language:
- English
Similar Records
Kinetics of Si monomer trapping at steps and islands on Si(001)
Correlated piecewise diffusion of a Ge ad-dimer on the Si(001) surface