Seminar

Halide Perovskite Memristors for Neuromorphic Computing Devices

 

Ho Won Jang

 

Department of Materials Science and Engineering, Seoul National University, Korea

 

E-mail: hwjang@snu.ac.kr

 

 

Halide perovskites, fascinating memristive materials owing to mixed ionic-electronic conductivity, have been attracting great attention as artificial synapses recently. However, polycrystalline nature in thin film form and instability under ambient air hamper them to be implemented in demonstrating reliable neuromorphic devices. In this talk, after the fundamental mechanisms and characteristics of perovskite-based memristors are elucidated, it is presented that we successfully fabricated vertically aligned 2D halide perovskite films (V-HPs) for active layers of artificial synapses. The films show moisture stability for several months. Unlike random-oriented HPs, which exhibit negligible current hysteresis, the V-HPs possess multilevel analog memristive characteristics, programmable potentiation and depression with distinguished multi-states, long-short-term plasticity, paired-pulse facilitation, and even spike-timing-dependent plasticity. Furthermore, high classification accuracy is obtained with implementation in deep neural networks. These remarkable improvements are attributed to the vertically well-aligned lead iodide octahedra acting as the ion transport channel, confirmed by first-principles calculations. This study paves the way for understanding HPs nanophysics and demonstrating their potential utility in neuromorphic computing systems.