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O: Fachverband Oberflächenphysik

O 20: Inorganic/Organic Interfaces: Growth III

O 20.1: Vortrag

Dienstag, 17. März 2015, 10:30–10:45, MA 005

Tetrahydrofuran adsorption mechanism on Si(001)-c(4x2): A systematic density functional study. — •slimane laref ralf tonner — Fachbereich Chemie, Hans Meerwein Straße, 35032 Marburg, Germany

The silicon surface plays a decisive role for semiconductor devices. Thereby, the adsorption of organic molecules on silicon can play a major role in increasing functionalizing these semiconductors and even improve device properties in the long term [1]. Small organic molecules preferably react with one dimer on the clean surface which is related to the unique reconstruction of the clean silicon (001) surface [2-5]. Recently, experimental results [6] showed that tetrahydrofuran (THF) molecules exhibited a two-step reactivity on the silicon surface. Starting from these findings, we carried out a systematic density functional theory study to elucidate the main chemical processes of THF on Si(001)-c(4x2). All computational investigations were carried out within Vienna ab initio simulation package [7]. However, for treating electron interactions all calculations were established by mean of Perdew, Burke and Ernzehof (PBE) for the exchange-correlation function [8]. In addition, for weak interaction we used semi-empirical dispersion correction terms (DFT-D3) with an advanced damping function [9]. We calculate the adsorption energies and the kinetic barriers as well as the key structures that characterize the chemical reactions on the surface. A notable conclusion of this study is that the dissociation of THF molecules is dominated by kinetic effects in terms of a barrierless dissociation across the dimer trough.