A photo sensor with one-direction memristive behavior based on silicon-oxide

Here, we proposed a nonlinear, silicon-based, and photosensitive memristor structure with oxide as the active layer. A three-layer sandwiched Metal/SiO2/n-Si structure was constructed using a thin SiO2 grown layer on n-Si. Two different electrodes, colloidal silver and sputtered copper, were studied as ion sources, and their behavior was examined. The current-voltage and pulse response characteristics were considered as the main outcomes under dark and light conditions. Set and reset threshold voltages of 5 V and -11 V were obtained with a memory window near 5 V by a sweeping voltage of ±12 V. Colloidal silver-based samples demonstrated a synaptic plasticity change (ON/OFF ratios up to 310). In contrast, in the Cu sputtered samples, nearly no synaptic plasticity was observed. Also, the device exhibited a resistivity change of about 29% in response to optical pulses in the visible spectrum range. The fabricated silver-based devices act like a nonlinear one-direction memristor and a photosensor based on the ions migration inside the SiO2 layer with spike-timing-dependent plasticity characters.