Enhanced out-of-plane piezoelectric effect in In_2Se_3/transition metal dichalcogenide heterostructures

摘要

The two-dimensional material α-In_2Se_3, which possesses both out-of-plane ferroelectricity and piezoelectricity in monolayer, opens opportunity for the smart material integration in a micro-electro-mechanical system. However, the piezoelectric response decreases with the decreasing thickness of α-In_2Se_3, hindering the application of few-layer α-In_2Se_3 in electromechanical transformation. In this work, we report a strategy to enhance the out-of-plane piezoelectric coefficients by constructing In_2Se_3/transition metal dichalcogenides (TMDs) heterostructures. Such a strategy shows great piezoelectric enhancement compared with monolayer In_2Se_3, and the largest e_(31) of 2.9× 10~(-10) C/m is achieved in MoS_2/In_2Se_3. A phenomenological model is further constructed to connect the piezoelectric coefficients with the polarizations of the heterostructures. Furthermore, the induced dipole moment strongly affects the band structure of heterostructures, yielding tunable light absorption. The proposed In_2Se_3/TMDs heterostructures represent an innovative strategy for the development of future efficient piezoelectric and are attractive for deployment in electromechanical systems.