Chemical Reactions in Monolayer Aromatic Films on Silicon Surfaces

The formation of thin films on solid surfaces can be limited by the structures of the molecules and protocols used to form the films. These limitations can be mitigated by performing additional chemistry on the thin films to modify the structures and attach molecules with specific electronic, optical, or magnetic properties. In the present work, aryl molecules were covalently grafted onto hydride-passivated Si(111) surfaces (Si−H) to form monolayer films. The reaction of the films with selected reagents produced polar films and films containing fullerenes and organometallic compounds. Fullerene molecules were attached onto the surfaces via monolayer films in two ways: diazonium salt reaction with pristine fullerene and reaction with N -methylfullerenepyrrolidone. The films were characterized by X-ray photoelectron spectroscopy and ellipsometry. The reactions expand our capabilities to produce thin films on silicon with potential applications in molecular electronics, optical devices, and other related areas.