Aligned MoO₂/MoS₂ and MoO₂/MoTe₂ Freestanding Core/Shell Nanoplates Driven by Surface Interactions

Controlling the growth of two-dimensional (2D) transition metal dichalcogenides (TMDCs) is an important step toward utilizing these materials for either electronics or catalysis. Here, we report a new surface-templated growth method that enables the fabrication of MoO₂/MoS₂ and MoO₂/MoTe₂ core/shell nanoplates epitaxially aligned on (0001)-oriented 4H-silicon carbide and sapphire substrates. These heterostructures are characterized by a variety of techniques to identify the chemical and structural nature of the interface. Scanning electron microscopy shows that the nanoplates feature 3-fold symmetry indicative of epitaxial growth. Raman spectroscopy indicates that the MoO₂/MoS₂ nanoplates are composed of co-localized MoO₂ and MoS₂, and transmission electron microscopy confirms that the nanoplates feature MoO₂ cores with 2D MoS₂ coatings. Locked-coupled X-ray diffraction shows that the interfacial planes of the MoO₂ nanoplate cores belong to the {010} and {001} families. This method may be further generalized to create novel nanostructured interfaces with single-crystal substrates.