Unpredictably Disordered Distribution of Hetero-Blended Graphene Oxide Flakes with Non-Identical Resistance in Physical Unclonable Functions

In this study, a new concept of physical unclonable functions (PUFs) is introduced comprising reduced graphene oxide (GO) materials. To create a disordered conductivity distribution, two types of GO are used: HGO, are produced by the conventional Hummers’ method, and PGO, produced by Brodie's method with an additional unique purification procedure. It is found that PGO becomes graphene-like after room-temperature chemical reduction. These two reduced GOs have a distinct conductivity difference of up to 10⁴ times. By blending these two materials, a random mixture is created that can generate a highly unpredictable electrical signal, serving as an ideal security key with strong randomness and uniqueness. The optimized PUF device, based on this approach, demonstrates excellent performance in generating secure keys.