Interfacial electronic structures between fullerene and multilayer graphene for n-type organic semiconducting devices

摘要

The interfacial electronic structure of fullerene (C_(60)) deposited on a multilayer graphene (MLG) film was measured using in situ ultraviolet photoelectron spectroscopy and X-ray photoelectron spectroscopy. The energy level alignment at the interface of C_(60)/MLG was estimated by the shifts in the highest occupied molecular orbital (HOMO) and the vacuum level during step-by-step deposition of C_(60) on the MLG. The shift of the HOMO level indicates that there is a small band bending at the interface of C_(60)/MLG. The vacuum level was shifted 0.06 eV toward the low binding energy with additional C_(60) on the MLG. The measurements reveal that the height of the electron injection barrier is 0.59 eV, while the hole injection barrier height is 2.01 eV. We present a complete interfacial energy level diagram for C_(60)/MLG.