Effect of Filament Discharge on Uprightness of Carbon Nanotwists Tightly-Adhered to Substrate

Abstract

Making carbon nanofibers stand up in a field electron emitter to obtain a good field emission property when emitters are fabricated by printing on a substrate has been proposed. In the fabrication process of carbon nanotwist (CNTw) field emitters, paste composed of an ethyl cellulose binder and carbon nanotwists (CNTws) is printed on the substrate. Filament discharge (FD) treatment is an excellent technique that makes CNTws stand up because large-area treatment is possible at a low cost. To solve the problems of weak adhesion between CNTws and the substrate and the generation of fragments during FD treatment, we added a silicone binder to the paste at 0.83–0.97%. The variations in the silicone binder content were compared by the scanning electron microscopy (SEM) observation of CNTw emitter surfaces. As the content decreased, the number of upright CNTws increased and the height of upright CNTws became uniform. We confirmed that the crystalline property of CNTws was not changed by the FD treatment when the silicone binder was added. Also, spark from the CNTw emitter was inhibited with the addition of the silicone binder and the field emission current density in the case with the binder was 200 µA/cm2 higher than that in the case without the binder.