nanosheets*

Jianhua Hao^1,2
1Department of Applied Physics, The Hong Kong Polytechnic University, Kowloon, Hong Kong, P. R. China
²The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen 518057, P. R. China
Email: jh.hao@polyu.edu.hk
Piezoelectric size effect leading to the suppression of piezoelectric response in classical thin-films limits the use of piezoelectric materials in thin-film form. 2D materials exhibit atomically thin layered structures held by van der Waals (vdW) weak force, presenting possibilities to overcome the obstacle. In this work, we report an enhanced out-of-plane piezoelectric performance in In₂Se₃/MoS₂ vdW heterostructure through interface engineering. The piezoelectric coefficient d₃₃ of the vdW heterostructure shows high value in the 2D layered system. By combining the experimental studies and calculations, the excellent piezoelectric properties result from the type II band alignment which causes a larger interfacial dipole moment. The strategy can be extended to other 2D materials. Therefore, the study is helpful for designing multifunctional coupling atomic-scale nanoelectronics devices.