Flexible HfO2-based ferroelectric memristor

The development of the next generation of flexible electronics for biomedical applications requires the implementation of flexible active elements, potentially microcontrollers. The further step in this direction includes the development of devices for data processing directly on-chip, in particular, devices for neuromorphic computing. One of the key elements put forward within this paradigm is the memristor—the device emulating the plasticity of biological synapses. Due to the internal temporal dynamics of conductance, second-order memristors exhibit the most natural emulation of a biological synapse. Among different types of second-order memristors, ferroelectric memristors show the best cell-to-cell and cycle-to-cycle reproducibility. Here, we demonstrate a flexible ferroelectric second-order memristor on a mica substrate based on the 5-nm-thick polycrystalline Hf0.5Zr0.5O2 film. The conductance (synaptic weight) modulation with ROFF/RON ratio ∼20 is achieved via the gradual switching of the ferroelectric domains affecting the potential barrier in the structure. The devices demonstrate high reproducibility and various synaptic functionalities, including paired-pulse potentiation and paired-pulse depression. Functional properties persist both during static bending and after more than 100 bending cycles with a radius down to 1 cm.