Oxygen-Mediated Topological Growth of MoS₂ for Symmetry-Anisotropy Coengineered Ultrafast Electronic Switching.

Abstract

Anisotropic 2D materials offer transformative potential for directionally programmable electronics, but the fundamental trade-off between structural symmetry and electronic anisotropy has limited their device applications. Herein, a topological engineering breakthrough is reported that simultaneously achieves pseudo-C₆ symmetry and high in-plane anisotropy in a star-like monolayer MoS₂ domain. Structural characterization identifies two distinct lattice alignment modes corresponding to the armchair (AC) and zigzag (ZZ) crystallographic orientations, differing by 30° azimuthal rotation, thus enabling angle-resolved anisotropic transistors with exceptional electron mobilities (µA_C = 84.06 cm² V^-1 s^-1, µ_ZZ = 57.80 cm² V^-1 s^-1) and widely tunable electronic anisotropy ratios (I_AC/I_ZZ) of up to 10.91. Leveraging this dual symmetry-anisotropy control, an ultrafast square-wave generators are demonstrated with orientation-programmable switching characteristics that achieve only 39 aJ per event energy efficiency. This work provides new insights into symmetry-anisotropy coengineering in 2D materials, providing a novel platform for designing energy-efficient, high-speed switching electronics.