Theoretical Studies on the Adsorption of Si and C Chains onto Unfaulted and Faulted Si(111) Surfaces
- Resource Type
- Article
- Authors
- Zhang, Ruijing; Quan Tian, Wei; Long Gu, Feng; Aoki, Yuriko
- Source
- The Journal of Physical Chemistry - Part C; May 2007, Vol. 111 Issue: 17 p6350-6356, 7p
- Subject
- Language
- ISSN
- 19327447; 19327455
Density functional theory and ab initio elongation-method-based calculations have been performed on the adsorptions of Si and C chains on unfaulted and faulted Si(111) surfaces and of Si chains on the Si(111)−OH surface. The C-chain adsorptions on the faulted and unfaulted Si(111) surfaces have almost the same geometries but different reaction energies. The C chain adsorbs more easily on the faulted Si(111) surface than on the unfaulted surface. The Si linkage atom is stabilized upon adsorption of a C chain on the unfaulted and faulted Si(111) surfaces. The band gap of a Si(111)−OH surface with an adsorbed Si chain and a Si−O linkage becomes narrower with respect to that of a clean Si(111)−OH surface. The local density of states of the Si substrate atom in the Si−O linkage shows that the electron peaks become more localized and stronger near the conduction band after the adsorption of the Si chain. Because of the replacement of the H atom bonded to the O atom by the adsorption of the Si chain, the energy range of the occupied molecular orbitals of the O linkage atom becomes broader near the band gap. The reaction energy of a C chain on the faulted Si(111) surface remains constant with C-chain length.