Mechanism of Benzene Mono layer Formation on Si(100)-2x1 Studied by Surface Differential Reflectance Spectroscopy
Résumé
The kinetics of benzene adsorption on a Si(100)-2x1 surface has been monitored using real-time surface differential reflectance spectroscopy. A model with two adsorption modes is confirmed where benzene binds to the silicon surface in tight-bridge (TB) and butterfly (BF) configurations. For the first time, the balance between these modes is probed continually as the adsorption progressed and the resulting kinetics is discussed. In a first stage, benzene adsorbs in the TB configuration until it reaches 17% of a monolayer. In the second stage, additional molecules adsorb in the BF configuration and TB gradually converts into BF. At saturation, about 50% of the dimers are occupied by BF. Moreover, a Monte Carlo simulation provides a proper description of the adsorption kinetics.