Remote heteroepitaxy of transition metal dichalcogenides through monolayer hexagonal boron nitride

As a very promising epitaxy technology, the remote epitaxy has attracted extensive attention in recent years, in which graphene is the most used interlayer material. As an isomorphic of graphene, two-dimensional (2D) hexagonal boron nitride (h-BN), is another promising interlayer for the remote epitaxy. However, there is a current debate on the feasibility of using h-BN as interlayer in the remote epitaxy. Herein, we demonstrate that the potential field of sapphire can completely penetrate monolayer h-BN, and hence the remote epitaxy of ZrS₂ layers can be realized on sapphire substrates through monolayer h-BN. The field of sapphire can only partially penetrate the bilayer h-BN and result in the mixing of remote epitaxy and van der Waals (vdWs) epitaxy. Due to the weak interfacial scattering and high crystalline quality of ZrS₂ epilayer, the ZrS₂ photodetector with monolayer h-BN shows the best performance, with an on/off ratio of more than 2 × 10⁵ and a responsivity up to 379 mA·W⁻¹. This work provides an efficient approach to prepare single-crystal transition metal dichalcogenides and their heterojunctions with h-BN, which have great potential in developing large-area 2D electronic devices.