  One-dimensional (1D) nanostructures - nanowires (NWs) - exhibit promising
properties for integration in different types of functional devices. Their
properties can be enhanced even further or tuned for a specific application by
combining different promising materials, such as layered van der Waals
materials and conventional semiconductors, into 1D-1D core-shell
heterostructures. In this work, we demonstrated growth of GaN-MoS2 and GaN-WS2
core-shell NWs via two different methods: (1) two-step process of
sputter-deposition of a sacrificial transition metal oxide coating on GaN NWs
followed by sulfurization; (2) pulsed laser deposition of few-layer MoS2 or WS2
on GaN NWs from the respective material targets. As-prepared nanostructures
were characterized via scanning and transmission electron microscopies, X-ray
diffraction, micro-Raman spectroscopy and X-ray photoelectron spectroscopy.
High crystalline quality core-shell NW heterostructures with few-layer MoS2 and
WS2 shells can be prepared via both routes. The experimental results were
supported by theoretical electronic structure calculations, which demonstrated
the potential of the synthesised core-shell NW heterostructures as
photocatalysts for efficient hydrogen production from water.
