Coexistence of photoresponse and light-induced memresistive characteristics in zinc oxide (ZnO)-reduced graphene oxide (rGO) bilayer thin film

We have investigated photo-response as well as resistive switching behaviour in hybrid zinc oxide (ZnO)/reduced graphene oxide (rGO) bilayer thin film, equipped through sol–gel process on an ITO coated glass substrate under the dark and variation of light illumination. This ZnO/rGO photodetector reveals a stout photocurrent dependency on the colour of the lights illuminating (white and red laser light), where the magnitude of photocurrent has been found to increase exponentially with the increase in energy of photons of the incident light. In the same device, we have observed resistive switching behaviour and polarity effect of SET/RESET bias similar to that exhibited by the non-volatile memory device (NVRAM). The R on (HRS resistance) and R off (LRS resistance) ratio R on / R off is approximately 60 at bias voltage 2 V. We have explained this feature in light of filament formation and biasing effect on it. Photo annealing has been done to reduce GO to rGO for fabricating this device on ITO-coated glass substrate. Our study on electrical characterization of the ITO/ZnO/rGO/Au device explores the coexistence of photo-response and memresistive characteristics, which could be potential for developing multifunctional photodetector with memory effect.