Coverage Effects On Phenol Adsorption On Si(l 00)2 X 1 As: A First Principle Calculation

摘要

We investigated the adsorption of a 6-dimers Si(100)2×1 surface as a function of coverage and adsorption type (molecular/dissociative) by first principle calculations. In particular, we performed calculations on models with 2, 3, 4 and 6 phenol molecules, corresponding to coverage Θ= 0.34, 0.5, 0.67 and 1. We found that total adsorption energy, when at least one phenol is in a molecular state is lower than the sum of the corresponding singly adsorbed molecules. The dissociative adsorption of multiple molecules, both in parallel and switched configuration is most favoured for a coverage Θ= 0.34 (2.6 eV per adsorbed molecule). This values decreases to 2.0 eV and remains constant till the coverage 1 is reached.rnThe energy barrier for the molecular-to-dissociated transition of a phenol molecule, in presence of another dissociatively adsorbed molecule is ～0.008 eV and it is similar to the value in case of single adsorption. Possible hydrogen displacements were also considered.