Effect of visible-light illumination on resistive switching characteristics in Ag/Ce2W3O12/FTO devices

Impact of Light on Coexistence of Memresistance, Meminductance, and Memcapacitance (MEMRIC) in Nanostructured Copper Oxide (CuO) Based Random Access Memory Devices

We demonstrated the coexistence of memresistance, memcapacitance, and meminductance non-volatile bipolar analog resistive switching in Cu (top electrode)/CuO (active layer)/SS (bottom electrode) memory devices with and without presence of the light. The onset of memcapacitance and meminductance is noticed from the pinched-shaped characteristics in the first and third quadrants. The variation in the scan rate also impacts the coexistence characteristics by shifting the intercept point for low resistance (LRS) and high resistance (HRS) states in positive and negative biasing voltages. The durability and retention are measured over a period of 150 cycles and 1500 s with and without light illumination. The slopes for the Weibull cumulative distribution plot for set/reset state with and without light are 106.80/114.23 and 70.21/102.25, respectively, suggesting that the stability of the device increases with light illumination. Interestingly, the memcapacitance disappears after 600 cycles and after 60 ∘ C ${{\rm {^\circ}C}}$ . The double logarithmic I-V characteristics suggest the trap-assisted conduction (higher slope >2) in the higher external electric field, and Ohmic behavior in the lower applied field region. Thus, the present study provides a way for low-power electronics and photoresistors together with memresistance, memcapacitance, and meminductance, simultaneously, i. e., MEMRIC in a single device.

Memristive Synapses with Photoelectric Plasticity Realized in ZnO1-x/AlOy Heterojunction

With the end of Moore's law in sight, new computing architectures are urgently needed to satisfy the increasing demands for big data processing. Neuromorphic architectures with photoelectric learning capability are good candidates for energy-efficient computing for recognition and classification tasks. In this work, artificial synapses based on the ZnO_1-x/AlO_y heterojunction were fabricated and the photoelectric plasticity was investigated. Versatile synaptic functions such as photoelectric short-term/long-term plasticity, paired-pulse facilitation, neuromorphic facilitation, and depression were emulated based on the inherent persistent photoconductivity and volatile resistive switching characteristics of the device. It is found that the naturally formed AlO_y layer provides traps for photogenerated holes, resulting in a significant persistent photoconductivity effect. Moreover, the resistive switching can be attributed to the electron trapping/detrapping at the trapping sites in the AlO_y layer.