Flexibility of fluorinated graphene based memristor structures: current flow model in a multi-barrier system under tensile strain

Abstract

The flexibility of two types of memristor structures with fluorinated graphene (FG) based active layers (FG with graphene islands on polyvinyl alcohol, FG/PVA, and films from nanoparticles of V2O5 capsulated with FG, FG/V2O5) under the tensile strain in bending conditions was investigated and compared in the present study. Both types of memristors show a similar mechanism of resistance switchings (current paths on traps without filaments). Multi-barrier model of current flow was used to estimate the barrier parameters connected to FG from experiments on resistive switching of memristor structures in the bending condition. The first type of structures (Ag/FG/PVA/Ag) demonstrates the record high values of flexibility: ON/OFF current relation is not changed up to 7% tensile strain created by bending. The second type of structures (Gr/FG/V2O5/Gr with graphene contacts) show a decrease in ON current already for tensile strain more than 2%. The similar mechanism of current flow allows us to use the similar theory for description of the current flow versus the tensile strain. In spite of different structures and morphology of memristors, the typical values of the barrier height extracted from the theoretical description were similar: ∼1.5 eV with an effective barrier thickness of ∼16.5 nm and ∼1.3–1.6 eV with thickness 13.5–15.0 nm for FG/PVA and FG/V2O5 structures, respectively. Increase in the barrier thickness over 19 nm in both cases leads to the strong decrease in ON current of memristors.