Preparation of Single-Crystal MoS2 Nanotubes and 1D Van der Waals Heterostructures

Abstract

Single-crystal MoS₂ nanotubes possess outstanding electronic and optoelectronic properties. However, previous attempts to synthesize MoS₂ nanotubes are hindered by poor crystallinity and the high strain energy required to roll a sheet with three atomic layers into a tubular structure. Here, the confined template growth of well-crystallized MoS₂ nanotubes encapsulated within carbon nanotubes, forming 1D van der Waals heterostructures, is reported. The growth of MoS₂ nanotubes is catalyzed by iron carbide. CNTs serve as nanoreactors and structurally confined templates, ensuring the growth of fine MoS₂ nanotubes. Water vapor is employed to manipulate the structure and morphology of resultant MoS₂. Free-standing MoS₂ nanotubes are obtained by removing outer CNTs with gentle plasma etching. This method demonstrate the power of coupling the catalytic effect and the space confinement in the growth of high-quality MoS₂ nanotubes, which may become a common strategy for the preparation of general 1D nanostructures of various transition metal dichalcogenides and other materials.