Recent advances on crystalline materials-based flexible memristors for data storage and neuromorphic applications

Memristors have recently emerged as promising contenders for in-memory computing and artificial neural networks,attributed to their analogies to biological synapses and neurons in structural and electrical behaviors.From the diversity level,a variety of materials have been demonstrated to have great potential for memristor applications.Herein,we focus on one class of crystalline materials(CMs)-based flexible memristors with state-of-the-art experimental demonstrations.Firstly,the typical device structure and switching mechanisms are introduced.Secondly,the recent advances on CMs-based flexible memristors,including 2 D materials,metal-organic frameworks,covalent organic frameworks,and perovskites,as well as their applications for data storage and neuromorphic devices are comprehensively summarized.Finally,the future challenges and perspectives of CMs-based flexible memristors are presented.

Forming-free flexible memristor with multilevel storage for neuromorphic computing by full PVD technique

Flexible resistive random access memory(RRAM) has shown great potential in wearable electronics.With tunable multilevel resistance states,flexible memristors could be used to mimic the bio-synapses for constructing high-efficient wearable neuromorphic computing system.However,the flexible substrate has intrinsic disadvantages including low-tempe rature tolerance and poor complementary metal-oxidesemiconductor(CMOS) compatibility,which limit the development of flexible electronics.The physical vapor deposition(PVD) fabrication process could prepare RRAM without requirement of further treatment,which greatly simplified preparation steps and reduced the production costs.On the other hand,forming process,as a common pre-programing operation in RRAM,increases the energy consumption and limits the application scenarios of RRAM.Here,a NiO-based forming-free RRAM with low set voltage was fabricated via full PVD technique.The flexible device exhibited reliable re sistive switching characteristics under flat state even compre s sive and tensile states(R=10 mm).The tunable multilevel resistance states(5 levels) could be obtained by controlling the compliance current.Besides,synaptic plasticities also were verified in this device.The flexible NiO-based RRAM shows great potential in wearable forming-free multibit memo ry and neuromorphic computing electronics.