## 1 Introduction  
After the development of consumer electronic products, semiconductor non-volatile memory (NVM) has become increasingly prevalent due to its high operation speed, low power consumption, and shock immunity. Flash memory is now mainstream for NVM devices. However, with continuous device scaling, physics limitations cause severe reliability issues. Therefore, many novel devices, such as magnetoresistive random access memory [1], ferroelectric memory [2], phase change memory [3], and resistive random access memory (RRAM) [4], have been proposed as next-generation NVM devices. Among these devices, RRAM, with a sample metal/insulator/metal structure and resistive switching behavior-induced applied voltages, is the most promising candidate.  
The resistance of a RRAM device can be reversibly switched between a high-resistance state (HRS) and a low-resistance state (LRS) using applied voltages. The resistive switching behaviors of RRAM devices are influenced by its material group, defect status, and device structure [5; 6], and the switching mechanisms are usually dominated by valence change mechanisms [7], thermochemical reactions [8], and electrochemical reactions [9]. The Cu/SiO2/Pt structure is a typical electrochemical reaction RRAM, and we previously investigated its resistive switching (RS) properties [9]. Cu ions were dissolved from the Cu electrode; thus, the formation and rupture of Cu conducting filamentswere responsible for the reversible RS mechanism. One of the most severe issues is large switching dispersion, which would cause a small switching margin and a complex circuit for memory applications. Therefore, several methods have been proposed to reduce the occurrence of switching dispersion. Cu nanoparticles (Cu-NPs) were embedded into the SiO\({}_{2}\) layer of the Cu/SiO\({}_{2}\)/Pt structure to enhance the local electrical field near Cu-NPs during the forming process, which reduced the switching dispersion [10]. In our previous work [11], a graphene oxide (GO) layer with a folded, layered structure was used to limit the number of formation sites of Cu conducting filaments, which reduced the switching dispersion in the atmosphere [12]. Although the Cu/SiO\({}_{2}\)/Pt structure had good RS properties in the atmosphere, it had poor RS properties in a vaporless environment [13], which could have caused problems after device packaging. We have already conducted a study in which we fabricated a Cu/Cu\({}_{x}\)O/SiO\({}_{2}\)/Pt structure to investigate its RS in a vaporless environment [13]. The Cu\({}_{x}\)O layer in the Cu/Cu\({}_{x}\)O/SiO\({}_{x}\)/Pt structure helped the dissolution of Cu ions from the Cu electrode into the SiO\({}_{x}\) layer, enabling electrochemical RS in a vaporless environment.  
Graphene is a two-dimensional material with superior electrical and mechanical properties [14], making it a very attractive material for many applications such as integrated circuits [15] and mechanical resonators [16]. Many methods, such as chemical vapor deposition [17] and reduced GO, attempt to fabricate low-price and large-area graphene layers. Oxygen functional groups within GO layers are influenced by synthesis methods and process parameters [18]. Therefore, GO is suitable for many applications. GO can be a surfactant due to its hydrophobic/hydrophilic property [19]. GO nanosheets are also a highly efficient and universal demulsifier [20]. In this study, a GO layer is inserted to fabricate a Cu/GO/SiO\({}_{2}\)/Pt structure. The GO film with numerous oxygen-related groups reacted with the Cu electrode to help the dissolution process of Cu ions into the SiO\({}_{2}\) layer. Therefore, the Cu/GO/SiO\({}_{2}\)/Pt structure can be resistively switched in a vaporless environment.