Enhanced out-of-plane piezoelectric effect in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>In</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi>Se</mml:mi><mml:mn>3</mml:mn></mml:msub></mml:mrow></mml:math>/transition metal dichalcogenide heterostructures
Yan‐Cong Chen, Zhiyuan Tang, Huili Shan, Bin Jiang, Yulong Ding, Xin Luo, Yue Zheng
Abstract
The two-dimensional material $\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{In}}_{2}{\mathrm{Se}}_{3}$, 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 $\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{In}}_{2}{\mathrm{Se}}_{3}$, hindering the application of few-layer $\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{In}}_{2}{\mathrm{Se}}_{3}$ in electromechanical transformation. In this work, we report a strategy to enhance the out-of-plane piezoelectric coefficients by constructing ${\mathrm{In}}_{2}{\mathrm{Se}}_{3}$/transition metal dichalcogenides (TMDs) heterostructures. Such a strategy shows great piezoelectric enhancement compared with monolayer ${\mathrm{In}}_{2}{\mathrm{Se}}_{3}$, and the largest ${e}_{31}$ of $2.9\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}10}\phantom{\rule{0.16em}{0ex}}\mathrm{C}/\mathrm{m}$ is achieved in $\mathrm{Mo}{\mathrm{S}}_{2}/{\mathrm{In}}_{2}{\mathrm{Se}}_{3}$. 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 ${\mathrm{In}}_{2}{\mathrm{Se}}_{3}$/TMDs heterostructures represent an innovative strategy for the development of future efficient piezoelectric and are attractive for deployment in electromechanical systems.