Spike-time dependent plasticity of tailored ZnO nanorod-based resistive memory for synaptic learning

• Published in: Journal of science. Advanced materials and devices Vol. 8; no. 4; p. 100617
• Main Authors: Patil, Shubham V., Mullani, Navaj B., Nirmal, Kiran, Hyun, Gihwan, Alimkhanuly, Batyrbek, Kamat, Rajanish K., Park, Jun Hong, Kim, Sanghoek, Dongale, Tukaram D., Lee, Seunghyun
• Format: Journal Article
• Language: English
• Published: Elsevier 01.12.2023
• Subjects: Analog memristor; Nanochannel switching; Neuromorphic electron devices; Spike-time dependent plasticity
• ISSN: 2468-2179; 2468-2179
• DOI: 10.1016/j.jsamd.2023.100617

Metal oxide resistive memory is a potential device that can substantially influence the current roadmap for nonvolatile memory and neuromorphic computing. However, common amorphous oxide-based resistive random-access memory suffers from high forming voltages that complicate circuit design and abrupt SET behavior incompatible with analog weight updates. To overcome such limitations, wurtzite ZnO nanorods were synthesized on a fluorine-doped tin oxide (FTO) substrate and a bipolar resistive memory with the Ag/w-ZnO/FTO stacking sequence was fabricated. The hexagonal NR morphology of w-ZnO with controlled vertical growth and nanochannel formation between the NRs were produced by in situ crystalline growth. This morphology enabled a forming-free switching and an analog switching effect that emulated neuromorphic functionalities such as potentiation–depression and complex spike-time dependent plasticity-based Hebbian learning rules. Importantly, the device exhibited nonabrupt switching behavior suitable for analog weight updates in neuromorphic computing in contrast to conventional resistive memory.