Resolidified Chalcogen Precursors for High-Quality 2D Semiconductor Growth

Two-dimensional (2D) semiconductors including transition metal dichalcogenides (TMDCs) have gained attention in optoelectronics for their extraordinary properties. However, the large amount and locally distributed lattice defects affect the optical properties of 2D TMDCs, and the defects originate from unstable factors in the synthesis process. In this work, we develop a method of pre-melting and resolidification of chalcogen precursors (sulfur and selenium), namely resolidified chalcogen, as precursor for the chemical vapor deposition growth of TMDCs with ultrahigh quality and uniformity. Taking WS2 as an example, the monolayer WS2 shows uniform fluorescence intensity and a small full-width at half-maximum of photoluminescence peak at low temperatures with an average value of 13.6 +/- 1.9 meV. The defect densities at the interior and edge region are both low and comparable, i.e., (9 +/- 3)x10(12) cm(-2) and (10 +/- 4)x10(12) cm(-2), indicating its high structural quality and uniformity. This method is universal in growing high quality monolayer MoS2, WSe2, MoSe2, and will benefit their applications.

Automated summary

We develop a method of pre-melting and resolidification of chalcogen precursors for chemical vapor deposition growth of 2D transition metal dichalcogenides (TMDCs), resulting in TMDCs with ultrahigh quality and uniformity. Taking WS2 as an example, the monolayer WS2 shows uniform fluorescence intensity and narrow photoluminescence peak, indicating high structural quality and uniformity. This method is also applicable to the growth of other TMDCs like MoS2, WSe2, MoSe2.