Graphene Memory Based on a Tunable Nanometer-Thin Water Layer

Developing reliable memory devices with stable information storage capability in water is important for environmental and healthcare applications. However, it is challenging because water easily causes current leakage and information loss in conventional memory devices. This article reports a transistor-based graphene memory for which writing/erasing is through controlling the nanometer-thin water layer between graphene and its silica support. Using an interfacial water layer with a tunable thickness to switch the graphene electron-trapping extent allows the device to function in water, which is completely different from any current memory mechanisms. Stable high- and low-conductance (ON and OFF) states can be achieved by applying positive and negative gate voltages to control the water layer thickness as the writing/erasing processes, which is supported by our atomic force microscopy and Raman spectroscopy experimental results and theoretical predictions. The high stability in water and reversible switching property based on the nanometer-thin insulating water layer could facilitate the realization of ultra-compact 2D nonvolatile memories for various underwater applications.