TY - JOUR
T1 - Dynamic study of W atoms and clusters on W (1 1 1) surfaces
AU - Fu, T. Y.
AU - Weng, W. J.
AU - Tsong, T. T.
N1 - Funding Information:
We would like to thank the staff at the University of California landfill for their permission to construct our field plots on their property. This project was funded by Caltrans Storm Water Quality RTA# 65A0236, Doug Brown, Caltrans contract manager.
PY - 2008/9/30
Y1 - 2008/9/30
N2 - Using a field ion microscope, the diffusion behaviors and atomic processes of W atoms and clusters on W (1 1 1) surfaces were observed directly. The activation energy of W clusters diffusion on W (1 1 1) as a function of cluster size has an oscillatory and increasing behavior. But, the activation energy of a single W atom is especially high. The compact geometric structures are more stable and have higher activation energies of surface diffusion than structures with extra atoms at the periphery. Besides the terrace diffusion, other atomic processes such as the ascending, descending, detachment motion on W (1 1 1) surfaces were also observed. Unlike the general systems, their occurrence temperatures are quite near. These experimental results were used to discuss the formation mechanism of single atom W tips.
AB - Using a field ion microscope, the diffusion behaviors and atomic processes of W atoms and clusters on W (1 1 1) surfaces were observed directly. The activation energy of W clusters diffusion on W (1 1 1) as a function of cluster size has an oscillatory and increasing behavior. But, the activation energy of a single W atom is especially high. The compact geometric structures are more stable and have higher activation energies of surface diffusion than structures with extra atoms at the periphery. Besides the terrace diffusion, other atomic processes such as the ascending, descending, detachment motion on W (1 1 1) surfaces were also observed. Unlike the general systems, their occurrence temperatures are quite near. These experimental results were used to discuss the formation mechanism of single atom W tips.
KW - Field ion microscopy
KW - Single atom tip
KW - Surface thermodynamics
KW - Tungsten
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U2 - 10.1016/j.apsusc.2008.02.130
DO - 10.1016/j.apsusc.2008.02.130
M3 - Article
AN - SCOPUS:51249109925
SN - 0169-4332
VL - 254
SP - 7831
EP - 7834
JO - Applied Surface Science
JF - Applied Surface Science
IS - 23
ER -