Tin (Sn)-based two-dimensional (2D) materials exhibit intriguing mechanical and optoelectrical properties owing to their non-centrosymmetric crystallinity and tunable band structures. A judicious integration of these individually decoupled properties is projected to introduce unparalleled functionalities into them, which remain largely unexplored. Herein, we develop wafer-scale tin selenide (SnSe_2–x, 0 < x < 1) 2D layers composed of thermodynamically stable coexisting phases of SnSe and SnSe₂ with distinct functionalities and identify a strong interplay between their mechanical and optoelectrical characteristics. Mechanically, they display a strain-dependent piezoelectricity upon an anisotropic deformation of convex vs concave bending. Optoelectrically, they present an optical pulse-induced potentiation and synaptic plasticity accompanying a wavelength-tunable photoconduction upon visible to near-infrared (IR) illuminations. Harnessing these two independent features in a coupled manner enables a drastic enhancement of their synaptic responsiveness by >40% with a piezostrain of <1%. These findings suggest opportunities for atomically thin semiconductors in mechano-optical neuromorphic device applications.

中文翻译：

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压电应变驱动的晶圆级共相硒化锡层中光学突触可塑性的双向增强


锡 （Sn） 基二维 （2D） 材料由于其非中心对称结晶和可调能带结构而表现出有趣的机械和光电特性。这些单独解耦的属性的明智集成预计将为它们引入无与伦比的功能，而这些功能在很大程度上仍未得到探索。在此，我们开发了晶圆级硒化锡 （SnSe_2–x， 0 < x < 1） 2D 层，该层由热力学稳定的 SnSe 和 SnSe₂ 共存相组成，具有不同的功能，并确定了它们的机械和光电特性之间的强烈相互作用。在机械上，它们在凸弯曲与凹弯曲的各向异性变形时表现出应变依赖的压电性。在光电方面，它们在可见光到近红外 （IR） 照明下表现出光脉冲诱导的增强和突触可塑性，并伴有波长可调的光导。以耦合方式利用这两个独立特征，可以在 <1% 的压电应变下将其突触反应性急剧增强 >40%。这些发现为原子薄半导体在机械光学神经形态器件应用中提供了机会。