An ab initio study of 3-aminopropyltrimethoxysilane molecule on Si(1 1 1)-(sqrt(3) × sqrt(3)) surface

DEMİREL G., DEMİREL G., ÇAKMAK M., Çaykara T., Ellialtıoğlu S. Ş.

Surface Science, vol.601, no.18, pp.3740-3744, 2007 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 601 Issue: 18
  • Publication Date: 2007
  • Doi Number: 10.1016/j.susc.2007.04.045
  • Journal Name: Surface Science
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.3740-3744
  • Keywords: density functional theory, self-assembled monolayer, Si(111) surface, SELF-ASSEMBLED MONOLAYERS, TOTAL-ENERGY CALCULATIONS, ADSORPTION, SI(111), ORGANOSILANES, CHEMISTRY, DYNAMICS, GOLD
  • TED University Affiliated: No


The chemisorption and reaction of 3-aminopropyltrimethoxysilane (APTS) molecule on the Si(1 1 1)-(sqrt(3) × sqrt(3)) surface are investigated by first principles density-functional calculations within the generalized gradient approximation. Before studying the chemisorption of APTS molecule on the surface, we have firstly put three -OH groups on the silicon surface, but considering six different locations for H and O atoms. Upon their relaxations, model II, which is assumed to be crosswise for initial orientation of -OH groups, was found to be energetically more favorable than the others. In model II, after the relaxation, its conformation was transformed to skewed structure due to the repulsive forces between -OH groups. Isolated APTS molecule was also investigated in order to obtain its most stable molecular geometry, for which the HOMO-LUMO gap was found to be 4.41 eV. In addition to these, after the energetically most favorable hydroxylated Si(1 1 1) surface was calculated, APTS molecule was chemisorbed on the surface by means of liberating its methoxy groups. In our model for the binding of APTS molecule on the Si(1 1 1) surface, the silicon atom in the APTS forms three bonds to hydroxyl groups at the surface. © 2007 Elsevier B.V. All rights reserved.