Direct Growth of Nanopatterned Graphene on Sapphire and Its Application in Light Emitting Diodes

Abstract

Direct growth of graphene films on functional substrates is immensely beneficial for the large-scale applications of graphene by avoiding the transfer-induced issues. Notably, the selective growth of patterned graphene will further boost the development of graphene-based devices. Here, the direct growth of patterned graphene on thec-plane of nanopatterned sapphire substrate (NPSS) is realized and the superiority of the patterned graphene for high-performance ultraviolet light-emitting diodes (UV-LED) is demonstrated. As confirmed by density functional theory calculations and analog simulations, compared to the concaver-plane the flatc-plane of NPSS is characterized by a lower active barrier for methane decomposition and carbon species diffusion, as well as a greater supply of carbon precursor for graphene growth. The synthesized patterned graphene on thec-plane of NPSS is verified to be monolayer and high quality. The patterned graphene enables the selective and well-aligned nucleation of aluminium nitride (AlN) to promote rapid epitaxial lateral overgrowth of single-crystal AlN films with low dislocation density. Consequently, the fabricated UV-LED demonstrates high luminescence intensity and stability. The method is suitable for obtaining various patterned graphene by substrate design, which will allow for greater progress in the cutting-edge applications of graphene.