The paper was published in Nanomaterials.
In this study, we investigated the resistive switching behavior of a lateral 2D composite structure consisting of bilayer graphene and diamane (2D diamond). We observed the local diamondization of bilayer graphene on a La3Ga5SiO14 substrate under focused electron beam irradiation. Raman spectroscopy analysis revealed an elevated density of sp3-hybridized carbon in the irradiated regions. The current-voltage characteristics of the bilayer graphene before and after the electron beam-induced transition demonstrated a significant increase in resistance upon the formation of the diamane structure.
Furthermore, the resistive switching behavior of a nanostructure consisting of bilayer graphene, diamane, and bilayer graphene was investigated. A voltage sweeps from 0 V to -1 V and then to 1 V and back to 0 V resulted in resistive switching from a high resistance state to a low resistance state and back. This switching behavior was attributed to the migration of hydrogen ions and/or oxygen-related groups, leading to the reduction of sp2 carbon bonds in the bilayer graphene.
In our theoretical investigation, we focused on understanding the influence of an electric field on the bonding of functional groups to the surface and the overall stability of a diamond film. To achieve this, we designed a graphene/diamane heterostructure, where the diamond layer is stabilized by oxygen atoms in the form of peroxide groups from the langasite substrate on one side and hydrogen atoms released from the PMMA coating on the other side. This model represents a diamond nanoribbon embedded within a graphene bilayer. The stability of the diamond film is closely tied to the strength of the C-O and C-H bonds. The presence of functional groups on the film surface contributes to its stability, and their desorption can lead to the cleavage of the film. Our simulations demonstrate that when a sufficiently strong electric field is applied to a lateral bigraphene/diamane/bigraphene nanostructure, it can induce the migration of oxygen-related groups. This migration process results in the breaking of interlayer sp3 carbon bonds and the disruption of the diamane structure. The alteration of the carbon bonding configuration and the disruption of the diamane structure play a crucial role in this process, enabling the system to exhibit distinct electrical properties and undergo reversible transitions between resistive and conductive states.
The results of this study highlight the potential of using bilayer graphene and diamane structures for resistive switching applications. The ability to control the conductive properties through electric voltage opens up possibilities for the development of novel memristor devices with improved performance. Further research can explore the optimization of the fabrication process and the integration of these structures into practical devices for various applications, including power-efficient implementation of artificial intelligence and advanced computing systems.