A gas-phase alkali-halide-assisted stable precursor supplied from zirconium carbide for the synthesis of 2D large-sized ZrS2 nanosheets†

Group-IVB transition metal dichalcogenides such as HfS₂ and ZrS₂ demonstrate the most promising semiconducting properties, with moderate band gaps and high predicted carrier mobilities. However, the lateral growth of large-domain-size single crystalline ZrS₂ nanosheets remains to be developed, which limits various electronic and optoelectronic applications. Here, we report a new precursor strategy for the synthesis of large-sized 2D ZrS₂ nanosheets with lateral orientations. Volatilization of high-melting-point zirconium carbide as a stable precursor was controlled through the assistance of a remote gas-phase alkali halide, which avoids high nucleation density and vertical orientation at the initial stage. The 2D ZrS₂ nanosheets were regulated by adjusting the growth parameters to give a lateral size of up to 22 μm and a thickness of 8 nm, and exhibited good crystalline qualities and a uniform surface. Field effect transistors of 2D ZrS₂ nanosheets exhibited n-type transport characteristics with a high on/off ratio and reasonable carrier mobilities. Our new precursor and chemical design pave the way for the synthesis of high-performance group-IVB transition metal dichalcogenide wafers.