Fig. 14
From: Status and Prospects of ZnO-Based Resistive Switching Memory Devices
a I-V characteristics of the crossbar ZnO RRAM device stacked with (a) a ZnO/NiO p-n junction and b WO3/ZnO tunnel barrier diodes. Inset of a and b: equilibrium band alignment of Pt/NiO/ZnO/Pt and Pt/ZnO/WO3/Pt. Solid circle denotes electron, open circle denotes hole, and arrows denote possible conduction mechanisms of carriers. The indicated energy values in the inset diagrams are calculated based on literature values (ref. [284, 285]) [247]