  Transferring graphene flakes onto hexagonal boron nitride (h-BN) has been the
most popular approach for the fabrication of graphne/h-BN heterostructures so
far. The orientation between graphene and h-BN lattices, however, are not
controllable and the h-BN/graphene interfaces are prone to be contaminated
during this elaborate process. Direct synthesis of graphene on h-BN is an
alternative and rapidly growing approach. Synthesized graphene via such
approaches is personally tailored to conform to each specific h-BN flakes,
hence the limitations of conventional fabrication approaches are overcome.
Reported processes paved the initial steps to improve the scalablity of the
device fabrication for industrial applications. Reviewing the developments in
the field, from the birth point to the current status is the focus of this
letter. We show how the field has been developed to overcome the existing
challenges one after the other and discuss where the field is heading to.
