Nonvolatile Memory Device Using Gold Nanoparticles Covalently Bound to Reduced Graphene Oxide

Abstract

Nonvolatile memory devices using gold nanoparticles (AuNPs) and reduced graphene oxide (rGO) sheets were fabricated in both horizontal and vertical structures. The horizontal memory device, in which a singly and doubly overlayered semiconducting rGO channel was formed by simply using a spin-casting technique to connect two gold electrodes, was designed for understanding the origin of charging effects. AuNPs were chemically bound to the rGO channel through a π-conjugated molecular linker. The π-conjugated bifunctional molecular linker, 4-mercapto-benzenediazonium tetrafluoroborate (MBDT) salt, was newly synthesized and used as a molecular bridge to connect the AuNPs and rGOs. By using a self-assembly technique, the diazonium functional group of the MBDT molecular linker was spontaneously immobilized on the rGOs. Then, the monolayered AuNPs working as capacitors were covalently connected to the thiol groups of the MBDT molecules, which were attached to rGOs (AuNP-frGO). These covalent bonds were confirmed by XPS analyses. The current-voltage characteristics of both the horizontal and vertical AuNP-frGO memory devices showed noticeable nonlinear hysteresis, stable write-multiple read-erase-multiple read cycles over 1000 s, and a long retention time over 700 s. In addition, the vertical AuNP-frGO memory device showed a large current ON/OFF ratio and high stability.

Metal-catalyzed azide-alkyne “click” reactions: Mechanistic overview and recent trends

“…Functionalized graphene and partially reduced graphene oxide (rGO) functionalized on the surface provide possibilities for improving the electrical strength recovery and utilization in devices. Functionalized rGO surface covalently immobilized with metal nanoparticles such as AuNPs and AgNPs, through the organic linkers is a good tool for achieving controllable transport in memory devices [202] and electron transfer in photocatalysis [203]. Click formation of 1,2,3-triazoles on the surface of rGO combined with localized surface plasmon resonance (LSPR) effect of the AuNPs allowed the observation of a fivefold photocurrent enhancement for triazole linkers.…”

Multilayer Graphene Nanoribbon and Carbon Nanotube Based Floating Gate Transistor for Nonvolatile Flash Memory

“…Graphene oxide thin films based flexible nonvolatile resistive memory has also been explored [5]. Graphene and graphene oxide have been investigated as FET channel, charge trapping layer and electrode in [14]- [19]. Large hysteresis in the gate characteristics of graphene FETs can be utilized for nonvolatile memory application [20].…”

Controlled charge trapping by molybdenum disulphide and graphene in ultrathin heterostructured memory devices

“…A number of reports have utilized graphene or graphene oxide in non-volatile memory devices, such as an FET channel, a charge-trapping layer or an electrode [16][17][18][19][20][21][22] . It was shown that the large hysteresis in the gate characterization curves of graphene FETs (GFETs) can be applied for memory device operation 23 .…”