Electronic structure of Si(111)-bound alkyl monolayers: Theory and experiment

We elucidate the electronic structure of both filled and empty states of ordered alkyl chains bound to the Si(111) surface by combining direct and inverse photoemission spectroscopy with first principles calculations based on density functional theory. We identify both filled and empty interface-induced gap states, distinguish between those and states extending throughout the monolayer, and discuss the importance of these findings for interpreting transport experiments through such monolayers.