1 Introduction Resistance random access memory (RRAM) has potential applications in many areas of transparent and flexible electronics because of its simple device structure, low power consumption, diversity of materials, and particularly high scalability, i.e., crossbar structure and multi-stacking memory architecture [1]. Researchers have proposed a number of metal oxides for RRAM applications, such as ZrO 2 , Al 2 O 3 , ZnO, TiO 2 , and NiO [2, 3]. Among these, ZnO is one of the most attractive materials for RRAM applications because of its high transparency, reliability, good ductility, and stable resistive switching (RS) behavior in a metal-insulator-metal (MIM) structure [4]. Recently, sol-gel methods have been widely used to grow ZnO thin films, owing to the low-temperature and simple fabrication processes applicable to flexible applications compared to sputtering and pulsed laser deposition [5]. Thus far, resistive switching behaviors on a flexible substrate have been reported only for ZnO thin films [3] but not for ZnO nanorods (NRs). Compared to RRAMs with thin films, a one-dimensional (1D) nanostructure can provide a localized vertical filament that allows for RS operation with a narrow dispersion of operating voltages [6]. On the other hand, the conduction filaments (CFs) in thin films are different with each switch, causing non-uniform