Transparent and Flexible Copper Iodide Resistive Memories Processed with a Dissolution-Recrystallization Solution Technique

This study explores a class of resistive memory candidates─simple binary halides─and demonstrates their efficacy in switching between high- and low-resistive states. Herein, copper halide, particularly copper iodide (CuI), is investigated for its resistive switching efficacy when sandwiched between indium tin oxide (ITO) and silver electrodes on flexible polyethylene terephthalate (PET) substrates. CuI is deposited on ITO-coated PET using an innovative dissolution-recrystallization technique, in which a deposition temperature of 80 °C is sufficient to eliminate the carrier solvent─acetonitrile─and impart considerable densification of CuI for effective memory characteristics. The PET/ITO/CuI is transparent (>90%), and the PET//ITO/CuI/Ag devices display states of notably low- and high-resistive states with a ratio of more than 10 within a voltage biasing range of −2.5 to +2.5 V. Additionally, the devices exhibit similar resistive states under bending stress. Halides (in particular, CuI) are, thus, introduced as a class of active materials for transparent and flexible resistive memories.