Heterogeneous integration of single-crystal materials offers great opportunities for advanced device platforms and functional systems. In this talk, I will introduce ‘epitaxy on 2D materials’ concepts as a new pathway for producing freestanding epitaxial membranes that can be hetero-integrated. I first present ‘remote epitaxy’ of thin films, where III-V and III-N thin films are grown on wafers coated with graphene or boron nitride and then exfoliated at the 2D interface with atomic precision. Next, I present epitaxy on nanopatterned graphene as another method, which enables selective nucleation and lateral overgrowth of III-V and Ge. The dislocation reduction mechanism and the exfoliation mechanics of these epilayers will be explained.
In the later part of the talk, I will introduce freestanding membrane-based applications that can be realized by the epitaxy-on-2D methods. First, full-color vertical microLEDs will be presented, which are formed by vertically stacking red, green, and blue layers for ultra-high pixel density. Next, I will show electronic skin (e-skin) devices capable of multi-modal sensing and wireless communication, which are enabled by remote epitaxial GaN nanomembranes. Lastly, I will discuss the future applications of hetero-integrated electronics.