IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Surface Science Wednesday Sessions
       Session SS1-WeM

Paper SS1-WeM7
Determination of Atomic Potential Energy for Pd Adatom Diffusion Across the W (111) Islands and Surfaces

Wednesday, October 31, 2001, 10:20 am, Room 120

Session: Surface Diffusion
Presenter: T.-Y. Fu, National Taiwan Normal University, R.O.C.
Authors: T.-Y. Fu, National Taiwan Normal University, R.O.C.
L.-C. Cheng, National Taiwan Normal University, R.O.C.
T.T. Tsong, Academia Sinica, Taiwan, R.O.C.
Correspondent: Click to Email
Using field ion microscopy (FIM), we have probed the diffusion behavior of Pd adatoms on W (111) surfaces and in the vicinity of surface steps. From the behavior of an adatom approaching the step from the upper terrace, we find the step to be reflective to Pd adatoms. The extra reflective barrier is determined to be 0.64±0.03 eV. The behavior of adatoms approaching the step from the lower terraces has also been studied. The activation energy for the step-up motion of Pd atoms of W (111) steps is 1.84 eV. The potential energy difference toward and away from the W (111) pole exhibits a free energy anisotropy of 0.013 eV. These experimental results of atomic processes are related to the phenomenon of impurity induced pyramidal facet formation.