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arXiv · 1708.09049

Out-of-plane Piezoelectricity and Ferroelectricity in Layered $α$-In2Se3 Nano-flakes

Yu Zhou·Di Wu·Yihan Zhu·Yujin Cho·Qing He·Xiao Yang·Kevin Herrera·Zhaodong Chu·Yu Han·Michael C. Downer·Hailin Peng·Keji Lai
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Abstract

Piezoelectric and ferroelectric properties in the two dimensional (2D) limit are highly desired for nanoelectronic, electromechanical, and optoelectronic applications. Here we report the first experimental evidence of out-of-plane piezoelectricity and ferroelectricity in van der Waals layered $α$-In2Se3 nano-flakes. The non-centrosymmetric R3m symmetry of the $α$-In2Se3 samples is confirmed by scanning transmission electron microscopy, second-harmonic generation, and Raman spectroscopy measurements. Domains with opposite polarizations are visualized by piezo-response force microscopy. Single-point poling experiments suggest that the polarization is potentially switchable for $α$-In2Se3 nano-flakes with thicknesses down to ~ 10 nm. The piezotronic effect is demonstrated in two-terminal devices, where the Schottky barrier can be modulated by the strain-induced piezopotential. Our work on polar $α$-In2Se3, one of the model 2D piezoelectrics and ferroelectrics with simple crystal structures, shows its great potential in electronic and photonic applications.

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Yu Zhou, Di Wu, Yihan Zhu, Yujin Cho, Qing He, Xiao Yang, Kevin Herrera, Zhaodong Chu, Yu Han, Michael C. Downer, Hailin Peng, Keji Lai. 2017-08-29. Out-of-plane Piezoelectricity and Ferroelectricity in Layered $α$-In2Se3 Nano-flakes. https://doi.org/10.1021/acs.nanolett.7b02198

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