Figure 3

(a) A current–voltage measurement of the Au–NiO–Au device. Memristive characteristics with gradual switching is shown by the device. With the continuous cyclic operation, the conductivity increases in the devices. This is observed independent of the bias range selected, as shown in (a,b). (c) Different voltage scanning speeds result in similar I–V characteristics with gradual switching of the resistance state in the device. For slow scanning speed, larger hysteresis is observed, and for a faster scanning rate, smaller hysteresis can be seen. (d) The conduction mechanism via the NiO nanoparticle thin films is evaluated by plotting log I–log V. Voltage range where different slopes of I–V are indicated. Small voltage region is characterized by Ohmic conduction. For higher voltage, the slopes increase higher values indicating different conduction mechanisms. (e) Trap Assisted Tunneling (TAT) model was applied to the conductivity of the NiO-based device. (f) The high voltage conduction indicates F–N tunneling and a transition to direct tunneling at smaller voltages. The transition is indicated by the minimum at V\(_{trans}\) = 1.3 V.