  Synthetic two-dimensional (2D) mono-elemental crystals, namely X-enes, have
recently emerged as a new frontier for atomically thin nanomaterials with
on-demand properties. Among X-enes, antimonene, the \b{eta}-phase allotrope of
antimony, is formed by atoms arranged in buckled hexagonal rings bearing a
comparatively higher environmental stability with respect to other players of
this kind. However, the exploitation of monolayer or few-layer antimonene and
other 2D materials in novel opto-electronic devices is still hurdled by the
lack of scalable processes. Here, we demonstrated the viability of a bottom-up
process for the epitaxial growth of antimonene-like nanocrystals (ANCs), based
on a Metal-Organic Chemical Vapor Deposition (MOCVD) process, assisted by gold
nanoparticles (Au NPs) on commensurate (111)-terminated Ge surfaces. The growth
mechanism was investigated by large- and local-area microstructural analysis,
revealing that the etching of germanium, catalyzed by the Au NPs, led to the
ANCs growth on the exposed Ge (111) planes. As a supportive picture, ab-initio
calculations rationalized this epitaxial relationship in terms of compressively
strained \b{eta}-phase ANCs. Our process could pave the way to the realization
of large-area antimonene layers by a deposition process compatible with the
current semiconductor manufacturing technology.
