Keywords: graphene oxide, unipolar resistive switching, RRAM, resistive RAM, random access memory, retention behaviour, NEM, nano–electromechanical effects, electrostatic attraction, aluminium ion diffusion, nanoelectronics, nanotechnology, nonvolatile memory
Retention behaviour of graphene oxide resistive switching memory
Graphene oxide (GO) has recently been proposed as one of the potential resistive switching materials for future nonvolatile memory applications. In this work, we present a flexible resistive memory device with the structure of aluminium (Al)/GO/indium tin oxide (ITO) fabricated at room temperature. The Al/GO/ITO devices show unipolar resistive switching behaviour with resistance ratio to over 30, and SET and RESET voltages for 5 V and 3 V, respectively. In addition, the Al/GO/ITO flexible memory can sustain over 250 cycling without any resistance window closure. However, the retention failures after 5000 s were observed owing to the sharp resistance increase of LRS, which is first observed in GO based resistive memory. The retention behaviour is examined intensively through various READ operations, including changing read interval time, read voltage and environment temperature. Supported by the results of these electrical measurements, it has been proved that NEM (Nano–Electromechanical) effects are responsible for the resistive switching and retention failure. The stacked GO flakes in the film joined to each other due to the electrostatic attraction and lead the device to LRS while separated by voltage–induced break and drive the device to HRS. Therefore, short read interval time, large read voltage and high temperature can help hold LRS resistance.