  Two-dimensional (2D) materials offer opportunities to explore both
fundamental science and applications in the limit of atomic thickness. Beyond
the prototypical case of graphene, other 2D materials have recently come to the
fore. Of particular technological interest are 2D semiconductors, of which the
family of materials known as the group-VI transition metal dichalcogenides
(TMDs) has attracted much attention. The presence of a bandgap allows for the
fabrication of high on-off ratio transistors and optoelectronic devices, as
well as valley/spin polarized transport. The technique of chemical vapour
deposition (CVD) has produced high-quality and contiguous wafer-scale 2D films,
however, they often need to be transferred to arbitrary substrates for further
investigation. In this Review, the various transfer techniques developed for
transferring 2D films will be outlined and compared, with particular emphasis
given to CVD-grown TMDs. Each technique suffers undesirable process-related
drawbacks such as bubbles, residue or wrinkles, which can degrade device
performance by for instance reducing electron mobility. This Review aims to
address these problems and provide a systematic overview of key methods to
characterize and improve the quality of the transferred films and
heterostructures. With the maturing technological status of CVD-grown 2D
materials, a robust transfer toolbox is vital.
