The role of molecular interactions in the functionalization of Si(111)H with organic molecules

M. F. JUAREZ; E. M. PATRITO; P. PAREDES OLIVERA

Bariloche

Congreso; 13th Internacional Conference on Solid Films and Surfaces; 2006

Using periodic density functional theory calculation, we theoretically study the formation and stability of ordered monolayers of methane, ethane, methanol and formic acid on Si(111)H as a function of the surface coverage. In good agreement with experimental results, we found that the ordered structure of the silicon surface is preserved at full coverage of methyl radicals. The interactions involved in the formation of the monolayer are: the strong Si-C covalent bond, hydrogen bonding between -OH and -COOH groups, repulsive interactions between H atoms in adjacent hydrocarbon chains, and repulsive interactions between hydrogen atoms of the hydrocarbon chains and the Si surface. In the case of methanol and formic acid functionalized silicon surfaces, the resulting monolayers are not stable at full coverage.