A fabrication method for field emitter array of carbon nanotubes with improved carbon nanotube rooting

Abstract

We have developed a technique for fabrication of a field emitter array (FEA) of carbon nanotubes (CNTs) to obtain a high emission current along with a high current density. The FEA was prepared with many small equidistant circular emitters of randomly oriented multiwall carbon nanotubes. The fabrication of a FEA substrate followed with deposition of titanium nitride (TiN) film on a tantalum (Ta) substrate and circular titanium (Ti) islands on the TiN coated Ta substrate in a DC magnetron sputtering coater. CNTs were dispersed on the substrate and rooted into the circular Ti islands at a high temperature to prepare an array of circular emitters of CNTs. The TiN film was applied on a Ta substrate to make a reaction barrier between the Ta substrate and CNTs in order to root CNTs only into the Ti islands without a reaction with the Ta substrate at the high temperature. A high emission current of 31.7mA with an effective current density of 34.5A/cm2 was drawn at 6.5V/μm from a FEA having 130 circular emitters in a diameter of 50μm and with a pitch of 200μm. The high emission current was ascribed to the good quality rooting of CNTs into the Ti islands and an edge effect, in which a high emission current was expected from the peripheries of the circular emitters.