Stretchable synaptic transistors based on the field effect for flexible neuromorphic electronics

Using flexible neuromorphic electronics that emulate biological neuronal systems is an innovative approach for facilitating the implementation of next-generation artificial intelligence devices, including wearable computers, soft robotics devices, and neuroprosthetics. Stretchable synaptic transistors based on field-effect transistors (FETs), which have functions and structures resembling those of biological synapses, are promising technological devices in flexible neuromorphic electronics owing to their high flexibility, excellent biocompatibility, and easy processability. However, obtaining stretchable synaptic FETs with various synaptic characteristics and good stretching stabilities is challenging. Significant efforts to produce stretchable synaptic FETs have been undertaken; and remarkable advances in materials, fabrication processes, and applications have been achieved. From this perspective, we discuss the requirements for neuromorphic devices in flexible neuromorphic electronics and the advantages of stretchable synaptic FETs. Moreover, representative methods used to implement stretchable synaptic transistors, including the structural design and development of intrinsically stretchable devices, are introduced. Additionally, the application of stretchable synaptic transistors in artificial sensory systems such as light, tactile, and multisensory artificial nervous systems is also discussed. Finally, we highlight the possible challenges in implementing and using stretchable synaptic transistors, propose solutions to overcome the current limitations of these devices, and suggest future research directions.