Crosstalk-Enabled High In-Plane Anisotropy of Monolayer MoS₂ Nanoribbons.

Abstract

Researchers now successfully fabricate well-aligned transition metal dichalcogenide (TMD) nanowires and nanobelts. However, achieving efficient carrier transport perpendicular to the nanowire direction remains a significant challenge, which continues to limit their application in integrated polarization-sensitive devices. Based on the synergistic mechanism of precursor anisotropic diffusion and step-edge-guided growth, an effective chemical vapor deposition (CVD) approach enabled by in situ coverage monitoring is developed to overcome existing limitations. By precisely terminating the growth process at its optimal stage, highly aligned and crosstalked monolayer MoS₂ nanoribbons (NRs) are obtained. Crucially, these NRs demonstrate efficient current conduction along both the parallel and perpendicular directions, enabled by the inter-ribbon crosstalk structures. Reflection difference spectroscopy (RDS) and polarized Raman characterization confirm strong in-plane optical anisotropy within the arrays. Electrical measurements reveal a remarkably high parallel-to-perpendicular current ratio of up to 63.2 at 30 V bias, enabling a distinct polarized light response. Furthermore, transient absorption (TA) spectroscopy uncovers anisotropic carrier dynamics in the NR arrays. This work represents the first demonstration of mimicking the differential electrical transport behavior characteristic of intrinsically anisotropic materials using an otherwise isotropic TMD material system, opening new possibilities for anisotropic optoelectronics.