Investigation on asymmetric resistive switching (RS) characteristics in p-NiO/n-ZnO heterojunctions

In this research, we report asymmetric resistive switching (RS) characteristics using p-NiO and n-ZnO heterojunctions. A cost-effective spray pyrolysis technique is adopted for the deposition of n-ZnO and p-NiO layers. The structural analysis of ZnO and NiO layers confirms the hexagonal wurtzite and cubic structure, respectively. The morphological analysis of the p-NiO/n-ZnO heterojunction confirms the presence of a multilayered structure. The heterojunction was stacked between top silver (Ag) and bottom indium doped tin oxide (ITO) electrodes, and the RS characteristics were investigated. The RS device exhibits asymmetric current-voltage (I-V) characteristics with an ON/OFF ratio calculated as 2.7 and stable endurance characteristics of 50 cycles. It was analyzed that the formation and rupture of conductive filaments through intrinsic defects modulated by the p-NiO and n-ZnO layers contribute to the observed asymmetric resistive switching (RS) behavior in the fabricated p-NiO/n-ZnO heterojunction.