Fabrication of transparent graphite grid using stencil lithography and its application in strain sensor

Abstract

Highly sensitive strain sensors are demonstrated by using the transparent graphite grid. Graphite films were synthesized via chemical vapor deposition using Ni foil and transferred onto target substrate. And the graphite films were patterned simply by reactive ion etching (RIE) with stencil mask. The prepared graphite grid showed excellent optical (84% of opti-cal transmittance at 550 nm wavelength), electrical properties (121 $\Omega / \Box$ of sheet re-sistance) and strain sensing performance (gauge factor of 111 at 0.18% of strain with 10 ms ~ 80 ms of response time). Furthermore, various hand motions were also successfully dis-tinguished by using an array of the graphite grid sensors attached on each finger. Because the stencil mask is reusable and the RIE is well-established technique, we believe that our method can be effective to fabricate the functionalized carbon structures for electronic de-vices including not only graphite but also a number of carbon-based materials.