Anomalous in-plane electrical anisotropy in elemental metal nanosheets

Abstract

Two-dimensional (2D) elemental metals, often overlooked owing to their lack of switching or dielectric properties, have the potential to exhibit unique properties unachievable by their bulk counterparts if their microstructure can be controlled. Here we propose an electrodeposition method that utilizes a confined 2D template to prepare elemental metal nanosheets with an aligned grain orientation, resulting in an exceptionally high in-plane electrical anisotropy of >103. Heterogeneous nucleation is initiated and the directed growth of the metal at the cathode is controlled within a channel whose size is smaller than the critical size of the nuclei. This leads to the formation of anisotropic microstructures, and consequently, the nanosheets exhibit anisotropic electrical properties. Unlike conventional field-effect transistors, devices employing a channel with two orthogonally separated conduction paths yield an exceptional on–off switching ratio exceeding 104. Our approach offers a promising route to produce various 2D elemental metals with properties different from those observed in their bulk counterparts and highlights the potential of anisotropic metallic nanosheets as switching elements.