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.