科研之友
微信
新浪微博
Facebook
分享链接
摘要
The adsorption of thiophene on Si(111)-(7 x 7) has been studied using density functional theory within the generalized gradient approximation. For all adsorption geometries that have been experimentally identified, equilibrium binding energies have been calculated using a full 7 x 7 supercell to a depth of six Si monolayers. Despite the structural heterogeneity of the surface, all adsorption geometries are calculated to have the same binding energy, irrespective of their location within the 7 x 7 unit cell. A parallel survey of chemisorption sites, performed with scanning tunneling microscopy, demonstrated that thiophene prefers the faulted half of the unit cell over the unfaulted half, and edge over corner sites, in agreement with previous experimental studies. The theoretical and experimental results suggest that the activation energy barriers for chemisorption are site dependent. The physical factors leading to site dependent activation energies are briefly discussed.
- 出版日期2009-9
