The interfacial electronic structure between pentacene and multilayer graphene

The electronic structure at the interface region between pentacene and multilayer graphene (MLG) was investigated by in situ ultraviolet photoelectron spectroscopy and X-ray photoelectron spectroscopy. The secondary electron cutoffs, highest occupied molecular orbital (HOMO), and core-level changes were measured after deposition of pentacene on MLG to investigate the electronic structure at the interface. From the results, it was confirmed that there was neither band bending nor an interface dipole at the pentacene/MLG interface, even though a vacuum level shift was observed due to the three-dimensional growth of pentacene. In addition, there was no chemical reaction observed at the interface. The complete interfacial energy level band diagram of pentacene/MLG was also obtained to confirm the hole and electron injection barriers.