Exploring resistive switching in flexible, forming-free Ti/NiO/AZO/PET memory device for future wearable electronics.

Resistive Random Access Memory (ReRAM) is an emerging class of non-volatile memory that stores data by altering the resistance of a material within a memory cell. Unlike traditional memory technologies, ReRAM operates by using voltage to induce a resistance change in a metal oxide layer, which can then be read as a binary state (0 or 1). In this work, we present a flexible, forming-free, ReRAM device using an aluminium-doped zinc oxide (AZO) electrode and a nickel oxide (NiO) active layer. The fabricated Ti/NiO/AZO/PET device demonstrates reliable bipolar resistive switching (BRS) with two distinct and stable resistance states, crucial for neuromorphic computing. Electrical tests showed stable high and low resistance states with set voltage (V) ≈ 5.4 V and reset voltage (V) ≈ 2.9 V, with endurance over 400 cycles and retention around 10³ seconds. Different conduction mechanisms were observed in high resistance state (HRS) and low resistance state (LRS) like ohmic and space charge limited current (SCLC). Electrical characterization under bending conditions demonstrated the device's performance and reliability, with minimal variation in V and V values. These results highlight the potential of NiO/AZO-based flexible ReRAM for high-density data storage and wearable electronics applications.