The lattice mismatch
between interesting 2D materials and commonly
available 3D substrates is one of the obstacles in the epitaxial growth
of monolithic 2D/3D heterostructures, but a number of 2D materials
have not yet been considered for epitaxy. Here, we present the first
molecular beam epitaxy growth of a NiTe2 2D transition-metal
dichalcogenide. Importantly, the growth is realized on a nearly lattice-matched GaAs(111)B substrate. Structural properties
of the
grown layers are investigated by electron diffraction, X-ray diffraction,
and scanning tunneling microscopy. Surface coverage and atomic-scale
order are evidenced by images obtained with atomic force, scanning
electron, and transmission electron microscopy. Basic transport properties
were measured confirming that the NiTe2 layers are metallic,
with a Hall concentration of 1020 to 1023 cm–3, depending on the growth conditions.
Thin crystalline layers of TaAs Weyl semimetal are grown by molecular beam epitaxy on GaAs(001) substrates. The (001) planes of the tetragonal TaAs lattice are parallel to the GaAs(001) substrate, but the corresponding in-plane crystallographic directions of the substrate and the layer are rotated by 45°. In spite of a substantial lattice mismatch (about 19%) between GaAs(001) substrate and TaAs epilayer no misfit dislocations are observed at the GaAs(001)/TaAs(001) interface. Only stacking fault defects in TaAs are detected with transmission electron microscopy. Thorough X-ray diffraction measurements and analysis of the in-situ reflection high energy electron diffraction images indicates that TaAs layers are fully relaxed already at the initial deposition stage. Atomic force microscopy imaging reveals the columnar structure of the layers, with lateral (parallel to the layer surface) columns about 20 nm wide and 200 nm long. Both X-ray diffraction and transmission electron microscopy measurements indicate that the columns share the same orientation and crystalline structure.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.