Structure and stability of n- and p-type intercalated multilayer graphene using Cs-C2H4, FeCl3 and MoCl5

Abstract

Multilayer graphene (MLG) sheets have found a wide variety of applications in the field of electronics. However, the electrical resistivity of MLG sheets is much higher than that of metals. Although some attempts have been undertaken to intercalate compounds such as FeCl3 into MLG in order to reduce resistivity, the stabilities of the resulting products were not always sufficient. Further, there have been few reports of air-stable intercalated MLGs with n-type conduction.In this study, we used three types of MLGs: MLGs synthesized via CVD with four graphene layers, those with over 30 layers, and exfoliated MLG from HOPG. Regarding the n-type compound, the co-intercalation of Cs and C2H4 into these MLGs was performed, and the structures and air-stabilities of the reaction products were determined. Meanwhile, for the p-type compound, the intercalation of MoCl5 and FeCl3 were also investigated. The Cs-C2H4-MLG were sufficiently stable, such that the initial stage-2 structure was maintained for four weeks in air. Further, the resistivity dropped to one fourth that of the MLG. Although MoCl5 and FeCl3 could be intercalated to MLGs, MoCl5 was more suitable to form air-stable compounds.