Direct growth of CVD graphene on 3D-architectured substrates for highly stable tactile sensors

A novel method was developed for the direct chemical vapor deposition (CVD) synthesis of graphene on a 3D-architectured insulator substrate, with a conformal and uniform contact formed between the graphene and substrate and with this composite applied to the fabrication of a highly sensitive 3D-architectured sensor. The synthesis involved a UV/ozone treatment of a 1,2,3,4-tetraphenylnapthalene (TPN) solid carbon source film on a pre-patterned 3D-structured substrate to result in an enhancement of the surface adhesion at the interface between the TPN film and the substrate, with this enhancement having prevented the sublimation of the TPN from the substrate at the temperature used to grow the graphene. The substrate-adhered TPN was fully converted, with low defect density, to graphene on the 3D-architectured substrate. The graphene synthesized in this way showed both excellent surface adhesion and continuity even at the sloping edges of the substrate, and can thus be used as electrodes or interfacial passivation layers in highly stacked 3D-structured electronic devices. Also, it was shown to improve the electrical operational stability of a fabricated electronic tactile sensor. The proposed method for the synthesis of graphene directly on 3D-architectured substrates is expected to have wide applications in highly integrated 3D-structured electronics.