Functionalization of Si(1Â 0Â 0) surface with benzonitrile molecules in an ultra-high-vacuum molecular evaporator

We investigated benzonitrile adsorption on Si(1 0 0) deposited in a home-made molecular source using scanning tunneling microscopy (STM). A high-purity molecular source was constructed for evaporation of organic molecules in the liquid phase. The molecular flux and deposition rate are stable over time and yield good control of the coverage level to less than one monolayer. The method described for creation of a molecular beam can be extended to various molecules in the liquid phase under ambient conditions and substrates. To confirm the reliability of our results, we used benzonitrile molecules on Si(1 0 0) as a substrate that is highly demanding in terms of the vacuum quality (residual gases and impurities) and level. The results were compared with previously obtained results using STM and theoretical methods. This simple molecular source yields enhanced measurement possibilities for different experimental systems without the need for significant investment or system modifications. A simple model is presented to predict the expected coverage and to evaluate device parameters appropriate for the evaporated material.