1. Key Laboratory of Optoelectronic Information Materials of Hebei Province
2. Key Laboratory of Brain-Like Neuromorphic Devices and Systems of Hebei Province
3. Hebei University
4. Baoding 071002
5. China
6. Department of Mechanical Engineering
7. National University of Singapore
8. Singapore 117576
9. Department of Electrical and Computer Engineering
10. Singapore 117583
11. Department of Materials Science and Engineering