Highly stable carbon nanotube field emitters on small metal tips against electrical arcing

Abstract

Carbon nanotube (CNT) field emitters that exhibit extremely high stability against high-voltage arcing have been demonstrated. The CNT emitters were fabricated on a sharp copper tip substrate that produces a high electric field. A metal mixture composed of silver, copper, and indium micro- and nanoparticles was used as a binder to attach CNTs to the substrate. Due to the strong adhesion of the metal mixture, CNTs were not detached from the substrate even after many intense arcing events. Through electrical conditioning of the as-prepared CNT emitters, vertically standing CNTs with almost the same heights were formed on the substrate surface and most of loosely bound impurities were removed from the substrate. Consequently, no arcing was observed during the normal operation of the CNT emitters and the emission current remained constant even after intentionally inducing arcing at current densities up to 70 mA/cm(2).