A selector device based on graphene–oxide heterostructures for memristor crossbar applications

Abstract

Most of the potential applications of memristive devices adopt crossbar architecture for ultra-high density. One of the biggest challenges of the crossbar architecture is severe residue leakage current (sneak path) issue. A possible solution is introducing a selector device with strong nonlinear current-voltage (I-V) characteristics in series with each memristor in crossbar arrays. Here, we demonstrate a novel selector device based on grapheneoxide heterostructures, which successfully converts a typical linear TaO x memristor into a nonlinear device. The origin of the nonlinearity in the heterostructures is studied in detail, which highlights an important role of the graphene-oxide interfaces.As present memory technologies approach the limit of miniaturization, the memristive devices [1] (often called RRAM when used as memory) emerge as a top candidate for next generation nonvolatile random access memory (NVRAM) due to many advantages [2][3][4][5][6][7][8][9][10][11]. However, their potential applications are hindered by the sneak path issue [12,13], which is induced by the residue leakage current originated from the crossbar architecture. For example, although TaO x -based memristors exhibit great performances [3,4,[14][15][16][17] including high switching speed, low switching power, and high erase/writing endurance, the linear I-V characteristics cause large leakage current from the half-selected and unselected devices and thus lead to a write/read failure when integrated in crossbar arrays. To solve this issue, a viable approach is to connect a selector unit [18,19], which has large I-V nonlinearity, in series with each crosspoint device. Substantial experimental efforts have been made in pursuing suitable selector devices, such as Si-based diodes [20], oxide tunnel barrier devices [21], and threshold switches [22]. However, these proposals have various technical challenges to overcome, including device scalability, process complexity, and performance variability [19]. Thus, the development of selectors based on new materials or structures is highly desirable toward memristor crossbar applications.As monolayer carbon atoms arranged in honeycomb lattice [23], graphene has drawn significant attentions of researchers in both academia and industry. Its applications in electronic devices have been extensively investigated in the last decade [24] due to its amazing properties such as high charge-carrier mobility [25], unique energy band structure [26], and excellent mechanical strength [27]. In previous studies, graphene has been proposed to replace conventional metals as a novel electrode material, where interesting threshold switching [28] and lower power consumption behaviors [29] were observed.Here, we report a selector device based on a Au/ TiO x /graphene/TiO x /Au structure. By connecting it in series with a Pt/TaO x /Ta memristor, we establish a oneselector one-memristor (1S1M) cell which successfully converts the linear Pt/TaO x /Ta memristor into a nonlinear device. Further investigations with temperature-...

The Band Energy Engineering on High Epoxy (Or Hydroxyl) Content Graphene Oxide

“…Therefore, all parameters that are related to the bandgap will be changed by the bandgap energy such as, density of state (DOS), carrier concentration and conductance. 9 Also, these parameters in°uence the memristor's resistance switching and current-voltage characteristics by a direct tunneling model or a standard quantum tunneling equation as 14 ;…”

An Organic Bipolar Resistive Switching Memory Device Based on Natural Melanin Synthesized From Aeromonas sp. SNS

“…The nonlinearity in the I – V results during positive bias suggested that the Ag/Melanin/SS memristive device is a highly nonlinear device. Such kind of nonlinearity is useful for the development of analog circuits, selector devices for crossbar memory application and chaotic circuits based on memristive devices. In addition to this, an anomalous negative differential resistance (NDR) effect is observed during the SET process, as shown in Figure b.…”

Research progress on solutions to the sneak path issue in memristor crossbar arrays

“…Especially, the endurance of a selector should be significantly greater than that of its series memristor because the selector is turned on for every programming and reading event. The tunneling barrier 37,38 and n–p–n 39 or p–n–p 40 junctions are commonly used in selectors. Ovonic threshold switching (OTS) behavior could also be used to achieve high nonlinearity for oxide capacitor devices; this requires the threshold resistive switching to occur transiently (less than 10 ns).…”