Field emission properties of carbon nanotubes grown on Co/TiN coated Ta substrate for cathode in microwave power amplifier

摘要

For field emitters as a cathode of traveling wave tube-microwave power amplifiers (TWT-MPA),field-emission (FE)properties of in situ grown carbon nanotubes (CNTs)onto electrically conducting substrate were systematically characterized.CNTs grown on the Co/TiN coated Ta substrate with properly controlled process exhibited the best FE property.The maximum current density and corresponding total emission current were 3.5 mA/cnr and ~ 1.7 mA at 21.6 V/jjim,respectively.Details on the correlation between the FE properties and the morphological parameters will be discussed.