Transferable GaN Films on Graphene/SiC by van der Waals Epitaxy for Flexible Devices

Van der Waals epitaxy (vdWE) of GaN films on two-dimensional (2D) materials can overcome a lattice mismatch during crystalline growth. Moreover, this type of epitaxy allows the GaN films to be released from 2D materials because of the weak van der Waals force. However, it is difficult to directly grow a single-crystalline film on graphene. Here, using metal-organic chemical vapor deposition (MOCVD), transferable single-crystalline GaN films are synthesized on multilayer graphene (MLG)/SiC. The films exhibit a flat and continuous surface morphology and c-axis orientation. Moreover, the GaN films are released from the graphene and transferred to flexible substrates by direct mechanical exfoliation. Furthermore, flexible ultraviolet (UV) photosensitive devices are fabricated and show excellent photoelectric performance in the UV-range. This research lays a foundation for the application of GaN films in foldable-display and flexible-devices.