Eutectic-vapor-driven low-temperature growth of high-crystallinity two-dimensional TMDCs

Two-dimensional (2D) transition-metal dichalcogenides (TMDCs) have emerged as promising semiconductors beyond the limits of conventional scaling. Yet, wafer-scale synthesis remains hindered by the pervasive generation of atomic defects that degrade electronic applications. Here, we develop a eutectic-vapor growth strategy that enables direct synthesis of highly crystalline 2D MoS2 at unexpectedly low temperatures. This method simultaneously avoids incomplete precursor reaction and the defect-promoting conditions inherent to high-temperature growth. First-principles calculations combined with ab initio molecular dynamics reveal that Mo–S precursors undergo a eutectic interaction with halide salts, producing volatile molecular growth species at reduced temperatures. Potassium ions adsorbed at the MoS2 edge substantially lower the incorporation barrier of reactive growth units, which is expected to reduce the propensity for defect formation during crystal growth. This eutectic-mediated growth mechanism provides a chemically grounded and broadly applicable route for low-temperature synthesis of 2D TMDCs with substantially reduced defect densities.