Role of the oxide in memristive quasi-1D silicon nanowires†

Abstract

Memristors are garnering significant attention due to their high similarity to biological neurons and synapses, alongside their unique physical mechanisms. Biosensors exhibiting memristive behaviour have demonstrated substantial efficacy in detecting therapeutic and biological compounds in the past decade. This report investigates silicon nanowire (SiNW)-based devices incorporating Schottky barriers, which exhibit potential for memristive behaviour. The SiNWs are fabricated between two nickel (Ni) pads, defined as 1.5 μm in length and 90 nm in width, then forming a quasi-one-dimensional (1D) back-to-back Schottky diode structure due to their large aspect ratio. After oxygen plasma treatment of the SiNW, this back-to-back diode structure begins to exhibit memristive behaviour. Our experimental data indicate that this behaviour is induced by superficial oxygen along the SiNW and is influenced by the contacts within the Schottky barrier and the intermediate silicon oxide layer. Furthermore, we have developed a mathematical model derived from the thermal emission equation of Schottky diodes to accurately characterize and understand this memristive behaviour. Thanks to this model, it is possible to accurately fine-tune the design of memristive devices for application in neuromorphic computing and memristive biosensing.