Direct and scalable edge-induced alloying of Mo1-xWxS2 via patterned MoS2 templates

Abstract

In this study, we introduce a novel edge-induced alloying mechanism in which etched edges of a pre-grown MoS2 film serve as an internal Mo source during metal–organic chemical vapor deposition (MOCVD). Patterned MoS2 templates with exposed edges were fabricated via photolithography and O2 plasma etching, followed by WS2 regrowth under standard MOCVD conditions. Mo atoms released from the edges migrated across the substrate surface, mixing with incoming W atoms to form Mo1-xWxS2 alloys. Raman spectroscopy confirmed alloy formation through characteristic A1g peak shifts and broadening. Complementary X-ray photoelectron spectroscopy (XPS) and spherical aberration-corrected scanning transmission electron microscopy (Cs-STEM) analyses revealed homogeneous Mo–W mixing with ∼40–50 at. % Mo. Alloy uniformity and reproducibility were preserved across various pattern sizes and inter-hole distances, even at the macroscale. These findings establish a scalable and reproducible edge-induced alloying mechanism, offering guidelines for the fabrication of transition metal dichalcogenide heterostructures and alloys with high structural precision.