Fabrication of graphite grids via stencil lithography for highly sensitive motion sensors

A graphite grid was fabricated using reactive ion etching with a stencil mask. The graphite film was synthesized through chemical vapor deposition on commercial Ni foil and was simply etched with a stencil mask using oxygen plasma during reactive ion etching. It had ∼85% optical transmittance at a 550-nm wavelength and ∼120 Ω/sq sheet resistance. Graphite grids placed on a human hand used to distinguish its motions showed high strain-sensing performance: its gauge factor ranged from 100 to 350, and its response times for strain loading and for release were short (10 and 80 ms, respectively). Because the graphite-based structures could be prepared in large quantities and because etching with a reusable stencil mask is very simple, mass production of high-performance motion sensors using the well-structured graphite grid is commercially feasible.