Oriented Growth and Stitching Epitaxy of Strongly Interlayer-Coupled Two-Dimensional PtSe2
Scalable growth of single-crystalline two-dimensional (2D) materials remains challenging, particularly for PtSe2, whose strong interlayer interactions favor vertical stacking over lateral growth. Here, we report a growth strategy combining single-crystal substrate engineering with alkali-assisted chemical vapor deposition. Localized prestrain and strain-relief annealing transform polycrystalline Au foils into centimeter-scale high-index single-crystal substrates, enabling the growth of dense, unidirectionally aligned millimeter-scale PtSe2 ribbons. NaOH-assisted growth further promotes lateral epitaxy while suppressing vertical overgrowth, allowing adjacent ribbons to stitch seamlessly into centimeter-scale continuous PtSe2 films with thicknesses down to the monolayer limit. The resulting films exhibit thickness-dependent electrical behavior, evolving from semiconducting to bipolar semiconducting and semimetallic characteristics. This work establishes a promising route toward scalable synthesis of strongly interlayer-coupled 2D materials.
