Fig. 5

Remote epitaxy of 2D materials on sapphire (Al₂O₃) substrates and the principle. a Optical microscopic image of GaN microcrystals (μCs) taken at around the boundary between graphene/Al₂O₃ and bare Al₂O₃ surfaces. Based on the red dotted line, the left is on graphene/Al₂O₃ and right is on bare Al₂O₃. Tilted-view SEM images of GaN μCs grown on b graphene/Al₂O₃ and c bare Al₂O₃. d Photograph of the thermal release tape after the delamination of polyimide-encapsulated GaN μCs. The inset of d shows a photograph of the substrate after the exfoliation process. e Flexible white μCs-LED matrix arrays fabricated by forming patterned electrodes. Figure reproduced from ref. [190], Elsevier