Memristive Biosensors Under Varying Humidity Conditions

We attempt to examine the potential of silicon nanowire memristors in the field of nanobiosensing. The mem- ristive devices are crystalline Silicon (Si) Nanowires (NWs) with Nickel Silicide (NiSi) terminals. The nanowires are fabricated on a Silicon-on-Insulator (SOI) wafer by an Ebeam Lithography Technique (EBL) process that allows high resolution at the nanoscale. A Deep Reactive Ion Etching (DRIE) technique is used to define free-standing nanowires. The close alignment between Silicon (Si) and Nickel-Silicide (NiSi) terminals forms a Schottky- barrier at their junction. The memristive effect of the fabricated devices matches well with the memristor theory. An equivalent circuit reproducing the memristive effect in current-voltage (I- V) characteristics of our silicon nanowires is presented too. The memristive silicon nanowire devices are then functionalized with anti-human VEGF (Vascular Endothelial Growth Factor) antibody and I-V characteristics are examined for the nanowires prior to and after protein functionalization. The uptake of bio- molecules linked to the surface of the memristive NWs is con- firmed by the increased voltage gap in the hysteresis curve. The effects of varying humidity conditions on the conductivity of bio- modified memristive silicon nanowires are deeply investigated