Adsorbed atoms, which promote or poison the chemical reactivity of a substrate, are crucial for catalysis, thin film deposition and etching. Our study is motivated by the unexpected experimental result that amines adsorbe on the Cl/Si(001) surface, but not on H/Si(001)[1][2]. The interaction between amine and the clean as well as Cl - terminatetd Si(001) surface has therefore been analysed from first - principles calculations using the VASP implementation of density functional theory in generalized - gradient approximation (DFT-GGA). We analyse the process of the adsorption of amine on the surface in detail, using ab initio thermodynamics including vibrational entropies and reaction kinetics. We show that the amine adsorption is in fact energetically favorable on Cl/Si(001) and a possible reaction path exists. In addition to the interface chemistry, also the implications of the molecular adsorption for the surface electronic properties are discussed.
References:
[1] A. J. M. Casey C. Finstad, Adam G. Thorsness, Surface Science 600, 3363 (2006)
[2] R.J. Hamers, Surface Science 600, 3361 (2006) |