Electroforming free enhanced resistive switching in reduced graphene oxide films embedded with silver nanoparticles for nonvolatile memory applications

Abstract

Abstract In this paper, the reduced graphene oxide (rGO)-based resistive random access memory (RRAM), embedded with Ag NPs, for nonvolatile memory applications has been investigated. The device exhibited enhanced I on/I off current ratio at lower switching voltage. The rGO-Ag thin film was deposited by spin-coating technique on an indium tin oxide coated glass substrate. Top contacts of aluminum (Al) were deposited by thermal evaporation technique for electrical measurements. The morphology of thin film has been characterized by scanning electron microscopy, and elemental quantification has been done using energy-dispersive x-ray spectroscopy. The structural and chemical analysis of thin film has been performed using x-ray diffraction (XRD) characterization and x-ray photoelectron spectroscopy, respectively. During applied potential, the device switches between two resistance states; low resistance state (LRS) and high resistance state (HRS). Initially when potential is applied across the device, the deposited thin film (rGO-Ag) was found in LRS which did not require initial forming voltage to activate the device. The requirement of this forming voltage may induce severe mechanical and electrical stress in the device and degrades the device performance. The rGO-Ag-based RRAM devices required (<1 V) to switch from LRS to HRS or vice versa with a large (∼103) on/off current ratio. The electrical stability of the devices has been tested for 4 × 103 s and repeatability for >60 cycles, which did not exhibit too much degradation. In rGO-Ag thin film-based RRAM devices, Ag NPs act as charge trapping sites, which results in enhanced switching characteristics. The trapping and detrapping mechanism of charges by Ag NPs is responsible for the enhanced switching characteristics in these films.